William, a learned and ingenious printer, was born at Edinburgh in the year 1740. His father, Alexander Smellie, who followed the occupation of a master-builder, is said to have been a classical scholar, and a writer of Latin verses. He belonged to the sect of reformed Presbyterians, more commonly described as Cameronians. He left two sons and three daughters. John, the elder son, followed his father's employment, and married a sister of the late James Ferrier, Esq. clerk of session. Two of his daughters were likewise married. Residing in the suburban street called the Pleasance, he sent his younger son to Duddingstone school, which is scarcely a mile distant. William Smellie was there initiated in the ordinary branches of education, including the Latin language; but he left school at the early age of twelve, and was destined to follow some mechanical employment. It was his father's original intention to bind him an apprentice to a staymaker, but some difference occurred as to the terms of the indenture; "and the young scholar was preserved from the mortifying drudgery of scraping whalebone, and stitching coats of armour to force the female form into every shape save that of natural elegance." On the first of October 1752, he was bound an apprentice, for six years and a half, to Hamilton, Balfour, and Neill, printers to the university.

To this occupation he applied himself with great assiduity, and he soon became conspicuous for the rapidity, as well as the correctness, with which he dispatched his work. With equal assiduity he devoted his evenings to the acquisition of knowledge. Two years before the expiration of his apprenticeship, his masters appointed him a corrector of the press, with a weekly allowance of ten shillings, which at that period was no despicable remuneration. His father was now dead, and two of his sisters were materially indebted to him for their support. During his apprenticeship, he was permitted to attend some of the academical lectures. The printing-office was within the precincts of the university buildings; "and he generally continued at work till he heard the bell ring for lecture, when he immediately laid down his composing-stick, shifted his coat, ran off with his note-book under his arm, and returned to his work immediately after lecture." The Edinburgh Philosophical Society having offered a silver medal for the most accurate edition of a Latin classic, Smellie set and corrected an edition of Terence, which obtained this prize for his employers. His edition, which bears the date of 1758, but was actually printed during the preceding year, has been described as immaculate; but of the literal accuracy of this description, we entertain some doubt. It is very elegantly printed, and is in all respects creditable to the Edinburgh press of that period. His apprenticeship was completed on the first of April 1759; and in the ensuing month of September, he agreed to transfer his services to the office of Murray and Cochrane. Here he was not only to perform the ordinary work of a corrector, but was likewise to collect articles for the Scots Magazine, and to make abstracts, extracts, or transcripts of such pieces as his employers should direct. He was moreover to lend his aid "in writing accounts, and, in cases of hurry in printing, in composing or case-work;" and in return for these various services, he was to receive a weekly salary of sixteen shillings.

It was one advantage of his new situation, that his employers allowed him three hours a-day for the prosecution of his academical studies; and thus, under peculiar circumstances, he was enabled to obtain a regular education. He not only studied the Latin, Greek, and Hebrew languages, but likewise mathematics, logic, rhetoric, moral, and natural philosophy. He besides attended all the medical courses, including the lectures on chemistry and botany. The Hebrew class he attended in the year 1758, with the immediate view of preparing himself to superintend the printing of Dr. Robertson's Hebrew Grammar. His course of study had thus been so regular and complete, that he was in a state of mature preparation for more than one of the learned professions. Some of his friends recommended the study of divinity; Dr. Buchan urged him to betake himself to the practice of physic; but the hazard of relinquishing a certain though small income for a very uncertain experiment, must have served to emancipate him to his original avocation. An early marriage fixed him more completely in the printing-office. His wife, Jane Robertson, was the daughter of an army-agent in London, who had once been opulent, but who finally left his family in indigent circumstances. Her mother was the cousin of Mrs. Oswald of Dunikier, and there were other family connexions described as genteel, but they do not appear to have rendered any service to Smellie or his children. The marriage took place in 1763, when he had only attained the twenty-third year of his age.

In the mean time, his love of learning suffered no abatement. In the year 1760 he had become a member of the Newtonian Society, a literary association chiefly composed of young men educated in the university. They held their weekly meetings in one of the class-rooms. At each meeting an essay was read by one of the members; and a subject, previously assigned, was discussed in due form. The essays were restricted to subjects of natural science, but the debates extended to a wider range. The list of members included various names which were afterwards conspicuously known; and among others, we find that of Robert Blair, the late president of the court of session. To this association likewise belonged Thomas Blacklock, Robert Hamilton, Alexander Adam, Henry Hunter, Samuel Charters, and William Buchan. After the interruption of their regular meetings as a society, some of the members continued for several years to hold a weekly meeting in a tavern, where they partook of a sober repast, and spent their evenings in literary and social conversation. With two very estimable members of this club, Dr. Hamilton of Aberdeen, and Dr. Charters of Wilton, Smellie always retained a friendly connexion. A new association, of which he acted as secretary, was formed in the year 1778, under the denomination of the Newtonian Club. Most of the other members were connected with the medical profession, and five of them either then were or afterwards became medical professors in the university. In the list of these associates we find the names of Dugald Stewart and James Gregory. No person was eligible unless he was a member of the Philosophical Society; and the meetings of the club were appointed to take place immediately after the close of each meeting of the society. The number of members was not to exceed twenty; and a single black ball was to exclude any candidate. The last of their regulations stands thus: "As this club consists entirely of philosophers, it would therefore be ridiculous to make any laws for its internal police."

For the different branches of natural history Smellie had evinced an early predilection. To the study of botany he devoted so much attention, that in 1765 his Dissertation on the Sexes of Plants gained the gold medal given by Dr. Hope. In this dissertation, which was inserted in the first edition of the Encyclopaedia, he strenuously opposed the doctrines of Linnaeus. The substance of it was incorporated in his Philosophy of Natural History; and his opinions were then controverted by Dr. Rotheram, afterwards professor of natural philosophy at St. Andrews. Of his proficiency in these studies we find a more conspicuous proof. While he was attending the botanical class, the professor sprained his leg so severely that for a considerable interval he was unable to meet his students; and on this occasion he selected Smellie to continue the course of lectures. In a botanic garden, lectures cannot be servilely read from papers, either written by the lecturer himself, or supplied by others.

On the 25th of March 1765 he commenced business as a printer, in conjunction with two brothers named Robert and William Auld, the former of whom was a solicitor. His private resources were obviously scanty; and two of his friends, Dr. Robertson, professor of oriental languages, and Dr Hope, professor of botany, advanced to him the sum of seventy pounds, which we reckon equivalent to two hundred in our present currency. This copartnery was dissolved within the space of less than two years, by the retirement of Robert Auld; but a new company, consisting of Balfour, W. Auld, and Smellie, commenced business on the 22d of December 1766. John Balfour, who was likewise a bookseller, had been a partner in the house of Hamilton, Balfour, and Neill. The new house published the Journal, a newspaper supposed to have been unprofitable. Their connexion only continued till the month of November 1771; and the modified firm of Balfour and Smellie continued the business from the twelfth of that month. Beside his share of the profits, the junior partner was to receive ninety pounds a-year, and he was bound to conduct the entire business of the office. His average income amounted to about £200. After an interval of more than two years, he easily obtained from Lord Kames the favour of his becoming surety to the Royal Bank for a cash-account to the extent of two or three hundred pounds. Their acquaintance had arisen from a series of anonymous strictures which he communicated to his lordship when the Elements of Criticism were passing through the press of Murray and Cochrane. The author requested the acquaintance of his nameless critic, and afterwards honoured him with various marks of his friendly attention. He incidentally mentions his supping with Lord Kames, in company with Hume and other guests. He was likewise a guest at the learned suppers of Lord Monboddo; and he reckoned Lord Hailes, as well as Lord Gardenstone, among the number of his friends and well-wishers.

Balfour and Smellie were appointed printers to the university. The chief advantage which attended this appointment was the profit of printing the dissertations written by candidates for medical degrees. Smellie likewise printed the theses written by candidates for admission to the Faculty of Advocates; and his knowledge of the Latin language was in both cases found very serviceable to the writers. He rendered material assistance to his friend Dr. Buchan, in the composition of a work which attained to very extensive popularity. This work, entitled "Domestic Medicine, or, a Treatise on the Cure and Prevention of Diseases," was published at Edinburgh in the year 1770. In the course of forty years, it is said to have passed through twenty editions, each consisting of 6000 copies, besides many pirated editions in Ireland and America, and some even in Britain. Of this treatise, Smellie was sometimes represented as the sole author; but it appears with sufficient evidence that the manuscript was placed in his hands, and that in preparing it for the press, he made many essential alterations in its form and style. It was so diffuse and redundant, that a single chapter, as originally written, would nearly have equalled the size of the entire book, as at first printed. These services were compensated with a bill for one hundred pounds.

Of Smellie's life, we have now arrived at an era which recommends him to the more particular regard of the writers and readers of the present work. The first edition of the Encyclopedia Britannica consisted of only three volumes, which began to be printed in the year 1771. The principal articles were written, compiled, or devised by him, and he prepared and superintended the entire publication. "As you have informed me," says a letter of Andrew Bell, the chief proprietor, "that there are fifteen capital sciences which you will undertake for, and write up the subdivisions and detached parts, conformably] to your plan, and likewise to prepare the whole work for the press, &c. &c., we hereby agree to allow you L200 for your trouble." If his capital sciences had not exceeded the old number of seven, this remuneration could scarcely have been considered as extravagant. One of his original articles, contributed to this edition, was that on Ether, which attracted a considerable degree of attention, and gave no small offence to Dr. Cullen, whose theory was there exposed, though without any mention of his name. From internal evidence, he was convinced that the article must have been written by his colleague Dr. John Gregory. He at length ascertained the real author; and this discovery, says the late Dr. Gregory, "gave occasion to the complete alteration and softening of the article Ether in the second and all the subsequent editions of the Encyclopaedia; so that nothing of it was allowed to remain that could give offence to Dr. Cullen."

Of the second edition of this work Smellie was offered a share, apparently a third, conjoined with the charge of editorship. This offer he unfortunately declined, and thus lost the only golden opportunity that fortune ever presented to him. "At the death of Mr. Macfarquhar, printer, in April 1793, the whole work became the property of Mr. Bell. It is well known that Mr. Macfarquhar left a handsome fortune to his family, all or mostly derived from the profits of the Encyclopaedia; and that Mr. Bell died in great affluence, besides possessing the entire property of that vast work; every shilling of which may be fairly stated as having grown from the labours of Mr. Smellie in the original fabrication of the work, which is confessedly superior, and all of which he and his family might have shared in equally with Mr. Bell and the other proprietor, if he had not been too fastidious in his notions, and perhaps too timid in his views of the risk which might have been incurred in the mercantile part of the speculation." His chief objection is stated, not with much probability, to have arisen from a difference of opinion as to the general plan: "because the other persons concerned, it has been said upon the suggestion of a very distinguished nobleman of the highest rank and most princely fortune, insisted upon the introduction of a system of general biography; which Mr. Smellie objected to, as by no means consistent with the title." If this statement is accurate, we consider the nobleman as decidedly right, and Smellie as decidedly wrong; inasmuch as the historical and biographical part of the work has recommended it to many readers, who do not feel an equal degree of interest in the arts and sciences. The perfection of such a work is to render it agreeable as well as instructive to the greatest possible number of readers. The second edition, consisting of 1500 copies, began to be published in 1776. The third, extending to no fewer than 10,000 copies of eighteen vo-

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1 Smellie's Philosophy of Natural History, vol. i. p. 245. 2 Gregory's Additional Memorial to the Managers of the Royal Infirmary, p. 188. 3 Kerr's Memoirs of the Life, Writings, and Correspondence of William Smellie, F.R.S. & F.A.S., vol. i. p. 363. Edinb. 1811, 2 vols. 8vo. Smellie afterwards embarked in a speculation which did not prove so lucrative. This was "The Edinburgh Magazine and Review," of which the first number appeared in the month of October 1773. The editor was Dr. Stuart, whose temper and discretion were not equal to his talents and learning. Smellie was one of five partners, including the editor; and besides printing the work at the ordinary rates, he "was regularly to compile the last half-sheet of every number, to consist of foreign and domestic occurrences, or the news-department, and other articles; to keep the accounts of the concern; to answer all letters relative to the concern; and to review certain articles, as should be agreed upon between him and Dr. Stuart." The work only extended to five volumes, closing with the number for August 1776. It was conducted with so much ability, that it might have run a more prosperous career, if the personalities of the editor, displayed within so narrow a field, had not excited a degree of hostility with which it was hopeless to contend. But the history of this work will be resumed in our notice of Gilbert Stuart.

Of the Society of Antiquaries, instituted at Edinburgh in 1780, Smellie was an original member. In 1781 he was elected Superintendent of the Museum of Natural History, which they proposed adding to their antiquarian cabinet. He afterwards published an "Account of the Institution and Progress of the Society of the Antiquaries of Scotland." Edinb. 1782, 4to. To this account he added a second part in 1784. He was elected to the office of secretary in 1793. This new institution excited the jealousy of some other learned bodies. The senate of the university presented a memorial to the lord advocate, remonstrating against the grant of a royal charter to the Society of Antiquaries, on the allegation that Scotland was too limited a country for two literary Societies; and proposing, that instead of granting such a charter, the king should incorporate a society under the designation of the Royal Society of Scotland. They further suggested "that the Society of Antiquaries would intercept the communication of many specimens and objects of natural history, which would otherwise be deposited in the museum of the university, and of many documents tending to illustrate the history, antiquities, and laws of Scotland, from being deposited in the library of the Faculty of Advocates. They likewise noticed that the possession of a museum of natural history might enable and induce the Society of Antiquaries to institute a lectureship of natural history, in opposition to the professorship in the university." Nor did the curators of the Advocates Library remain inactive. They represented to the lord advocate that the grant of a charter to the Antiquaries "might prove injurious to that magnificent library, by intercepting ancient manuscripts and monuments illustrative of the history and antiquities of Scotland, which would be more useful when collected into one repository than in a state of division." To all these representations the Society returned an elaborate answer, in the form of a memorial addressed to the lord advocate; and the royal charter was finally ratified in the month of May 1783. It is scarcely necessary to add, that few or none of the multifarious evils which had thus been predicted, were found to result from the incorporation of this Society, which has proved almost as harmless as any institution in the kingdom. The Royal Society of Edinburgh soon afterwards obtained its charter; and as a member of the Philosophical Society, Smellie was incorporated on the 23rd of June 1783.

At the request of the Society of Antiquaries, he had in 1781 digested the plan of a statistical account of all the parishes of Scotland. The circulation of this plan did not excite much industry; but, at no distant period, it was followed by an extensive and important work. As superintendent of the museum, he was authorized to deliver in their hall a course of lectures on natural history. His object was to deliver lectures on the philosophy of natural history, which is a subject totally different from what a public professor is obliged to teach. A professor must instruct his students in the technical and elementary part of the science; but the private lecturer was to confine himself to general views of the economy of nature. The professor of natural history, who certainly had reason to fear such a rival, was alarmed at what he considered as an encroachment on his province, and this plan of lectures was reluctantly abandoned. On the death of Dr. Ramsay in the year 1775, Smellie had offered himself as a candidate for the professorship; but his claims were disregarded, and it was bestowed upon Dr. Walker, at that time minister of Moffat, and afterwards of Colinton.

Smellie however continued to prosecute his favourite study, and he published "Natural History, general and particular, by the Count de Buffon: translated into English. Illustrated with above 200 copper-plates; and occasional notes and observations by the Translator." Edinb. 1781, 8 vols. 8vo. "Much the greater portion of this extensive work," says Mr. Kerr, "was executed in a small correcting room or closet connected with his printing-office, where he was continually liable to interruption, from the introduction of proof-sheets for correction, and revises for comparison, and to the almost perpetual calls of customers, authors, and idle acquaintances: yet such was his accuracy of self-possession, that, as usual with almost every thing he wrote, he gave it out page by page, as fast as written, to his compositors, and hardly ever found it necessary to alter a single word after the types were set up from his first uncorrected manuscript. Although, to have enabled him to execute this translation in the excellent manner in which it is done, Mr. Smellie must necessarily have possessed a very thorough knowledge of the French language, it appears that he had acquired this entirely by means of his own private study, and without the assistance of any teacher; for we have been assured by those who knew him very intimately, that he was quite unequalled with the pronunciation of French."

A second edition of his translation, in nine volumes, followed in the year 1785. Other three editions, all of them extensive, were afterwards published; so that the work may be considered as having been eminently successful. The translator's notes were allowed to have added no considerable value to the text; and the chief fault imputed to him was the use of provincial idioms. He was honoured with the correspondence of Buffon, and likewise of Pennant.

The firm of Balfour and Smellie having been dissolved, that of Creech and Smellie began business on the 14th of September 1782, and continued it till the close of the year 1789. Creech, well-known as a bookseller, was in all cases difficult to bring to a settlement of accounts, when he had any reason to believe the balance to be on the wrong side. The affairs of this copartnery, being somewhat intricate, were submitted to arbitration, and a balance was ultimately found due to Smellie; but the decision was so long deferred, that it was not pronounced till some time after his death. After the termination of these different partnerships, he continued the business on his own account. Lord Kames died in the year 1782; and he was now indebted to the kindness of Lord Gardenstone, who became his surety to the banking-house of Sir W. Forbes and Co.

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1 Smellie's Account of the Society of Antiquaries, part ii. p. 24. His next publication was "An Address to the People of Scotland, on the Nature, Powers, and Privileges of Juries. By a Jurymen." Edinb. 1784, 8vo. This tract is entitled to particular notice, because it contains a clear and judicious exposition of legal principles, very important in themselves, and at that period very little understood. "It is," he remarks, "a common notion that jurors are judges of the fact only, and not of the law." This absurd, and often fatal prejudice is much more prevalent than might be expected, in a city like this, where general knowledge ought to be pretty widely diffused. It has perhaps been too much fostered by the injunctions of judges and magistrates. It is exceedingly natural that plain simple jurymen should look up with veneration to the high rank, and superior abilities of those men who are appointed by their sovereign to dispense justice over the nation. For this reason it is, that the English judges are so extremely solicitous not to inculcate their own opinions on the minds of jurymen, but to leave their determinations solely to the dictates of their own consciences. But from whatever source this prejudice may have derived its origin, I shall endeavour to show that it has neither law nor common sense for its support.

A further specimen may very satisfactorily be produced. "I know it to be the opinion of many jurymen, that after the court admits a relevancy, they are bound by their oaths to find the libel either proved or not proved. But these gentlemen should consider, that their business is to give a verdict of a very different kind. They are to judge both of the criminality of the culprit, and of his exculpatory evidence. The words proved or not proved should be for ever banished from the verdicts of juries. A relevancy may be found, when the jurymen, who hear the indictment impugned, are of an opposite opinion from the court. A crime may be libelled, when the facts related in the indictment, though completely proved, do not constitute the essence of the crime charged. Hence, whenever the minds of jurymen are convinced that a relevancy has been improperly found, their verdict, however the proof may stand, should be Not guilty. Indeed, the expressions, Guilty or Not guilty ought alone to be employed in verdicts." This tract excited a considerable degree of attention; and it was quoted with much approbation by Lord Erskine, in his famous speech in defence of Dr. Shipley, dean of St. Asaph. He published several other pamphlets, which chiefly related to local politics.

But the most elaborate of his works is "The Philosophy of Natural History." Edinb. 1790, 4to. This is an ingenious book, written in a very pleasing style, and it accordingly experienced a favourable reception. It was reprinted at Dublin and Philadelphia. Lichtenstein published a German translation, to which some notes were added by C. A. W. Zimmermann. For the original volume, Charles Elliot agreed to pay one thousand guineas, at six, twelve, and eighteen months, as well as a certain sum for every edition after the first. This enterprising bookseller died before the work was ready for publication; but the agreement was honourably fulfilled by his trustees, though the benefit accrued, not to the author himself, but to his family. "This," says Mr. Kerr, "was probably the largest sum that had ever been given, at least in Edinburgh, for the literary property of a single quarto volume, and evinced both the liberality of the bookseller, and the high estimation in which he very justly held the fame and talents of the author."

His plan however was not yet completed, and he immediately applied himself to the preparation of a second volume. He lived to bring it to a conclusion, though not to make any arrangement for its publication. During the last years of his life, his health appears to have been infirm and precarious. In June 1793, he stated to his friend Dr. Hutton, that he had for several months been distressed with a debility in his limbs, accompanied with a want of appetite; and to another medical friend, Dr. Gardiner, we find him stating very unfavourable symptoms in the course of the following year. After a long illness, he died on the 24th of June 1795, at the age of sixty-five. He left a widow, with four sons and four daughters; two sons and three daughters having died before their father. His eldest daughter was married to Mr. George Watson, an eminent portrait-painter in Edinburgh. Smellie had never been in affluent circumstances, but he left to his family the means of prosperity; and the printing business has been more successfully conducted by his son Mr. Alexander Smellie.

Of his Philosophy of Natural History, the second volume was published by this son in the year 1799. Another posthumous work speedily followed: "Literary and characteristic Lives of John Gregory, M.D., Henry Home, Lord Kames, David Hume, Esq., and Adam Smith, LL.D. To which are added a Dissertation on Public Spirit, and three Essays." Edinb. 1800, 8vo. His original plan comprehended the lives of other twenty-five men of literary eminence, with whom he was personally acquainted. One of these was his friend Dr. Stuart, with whose private history he was sufficiently familiar, and of which he could have supplied very curious, though perhaps not very edifying details. It is not however a subject of much regret that his plan was never completed. In the specimen with which we have thus been presented, there is too little biography, and too much discussion. This remark is more particularly applicable to the life of Dr. Gregory, which extends to 118 pages, but is almost entirely occupied with an account, not of the writer, but of his writings. The other lives are of less extent. In his account of Hume, he relates, without any symptom of disapprobation, the indecent levity with which he sported on the verge of another world; and in the same manner he likewise repeats the declaration of Dr. Smith as to the character of that philosopher, "I have always considered him, both in his lifetime and since his death, as approaching as nearly to the idea of a perfectly wise and virtuous man, as perhaps the nature of human frailty will permit." This ingenious printer may himself have been somewhat too anxious to be classed among philosophers.

Smellie appears to have been a man of excellent talents, and of extensive knowledge. His disposition was social, his habits were convivial, and he was distinguished by a sarcastic vein of wit and humour. According to the description of his biographer, he "was about the middle size, and had been in his youth well-looking and active; but when rather past the middle of life, he had acquired from almost constantly stooping at his desk to write or correct, a rather lounging gait and appearance; and from a long-continued series of difficulties in his affairs, and much disappointment in matters of affectionate moment, he had become careless and rather slovenly in his dress and appearance; wearing his hair long and bushy, his ordinary black and wide-made clothes ill brushed, and well sprinkled with snuff, and his usual old-fashioned cocked hat for the most part rusty." Burns describes him as "a man positively of the first abilities and greatest strength of mind, as well as one of the best hearts and keenest wits, that he had ever met with." And in the following lines, which allude to a club called the Crochallan Fencibles, he has exhibited a graphic delineation of Smellie:

To Crochallan came The old cock'd hat, the brown surtout the same; His bristling beard just rising in its might, 'Twas four long days and nights to shaving-night; His uncombed grizzly locks, wild staring, thatch'd; A head for thought profound and clear unmatch'd; And though his caustic wit was biting, rude, His heart was warm, benevolent, and good.

SMELLING is the act by which we perceive smells, or become sensible of the presence of odorous bodies. The Smeiling sensations of smell are excited by certain effluvia, which, in the open air, are always issuing from the surfaces of most bodies, and striking on the extremities of the olfactory nerves, give them a peculiar sort of impression, which is communicated to the brain. The particles which issue thus from bodies are extremely volatile, and produce sensation by a degree of contact, which, though insensible, is still more efficient than if it were more gross and palpable. It is by a similar species of insensible contact that the eyes and ears are affected by external objects; while, in the excitation of the sensations of touch and of taste, an actual and sensible contact of the object with the organ is necessary. The organs of smelling are the nostrils and olfactory nerves; the minute ramifications of the latter being distributed throughout the whole concavity of the former.

The effluvia from odoriferous bodies are constantly floating about in the atmosphere, and must of course be drawn into the nostrils along with the air in inspiration; so that there is," as Dr. Smith observes, "a manifest appearance of design in placing the organ of smell in the inside of that canal through which the air is continually passing in inspiration and expiration." It has been affirmed by Boerhaave, that the matter in animals, vegetables, fossils, and the like, which chiefly affects the sense of smelling, is that attenuated substance, inherent in their oily parts, called spirits; because, when this is taken away from the most fragrant bodies, what remains has scarcely any smell at all; but this, he says, if poured on the most indolent bodies, gives them a fragrancy. We cannot however enter at present upon this inquiry.

The sense of smell has a close alliance with that of taste; and it seems probable from the proximity in the situation of their organs in all animals, that both are principally intended to guide them in the choice of their food; so that from this close connection, they are better enabled to choose what is good for them, and to reject what would be injurious. This is the opinion of Dr. Reid, as it was, in a very early period of the history of philosophy, that of Socrates and of Cicero. Dr. Reid also remarks, that the sense of smell probably serves the same purpose in the natural state of man; but it is not always a sure guide for this purpose. The organs of smell differ, like those of the other senses, according to the destination of the animals to which they belong; and we know, that this sense is in man much less acute, than in many other animals. We see, that in the choice of their food, they are guided by the senses of smell and of taste, except when man has brought them into a sort of unnatural state by domestication. And this circumstance renders it probable, that both these senses were intended to serve the same purpose in the natural state of our species, although less calculated for this end than they were in the brutes, on account of the great superiority of their smelling organs. Besides, since it is probable that man, in the natural state, acts more by instinct than when civilized in society, so also it is reasonable to think, that he may possess some of the senses, this of smell for instance, in greater acuteness than we do. This indeed we are assured to be a fact; for we are told in the Histoire des Antilles, that there are negroes who, by the smell alone, can distinguish the footsteps of a Frenchman from those of a negro.

The sense of smell is much more obtuse in man than in some of the lower animals. Dogs we know possess a power of smelling, of which we can scarcely form a conception; and which it is happy for us we do not possess; and birds of prey are said to possess this sense in still greater acuteness. But although this be more perfect, still the sense of smelling in man, who has other means of judging of his food, is such as to fit him for deriving enjoyment from a diversity of scents, particularly those of flowers and perfumes, to which dogs and other animals seem perfectly insensible. It has been said, we are aware, that some animals, the elephant for instance, are capable of this enjoyment; but of this fact we cannot help being very doubtful.

There is a very great sympathy between the organs of smell and of taste; for any defect or disease of one is generally attended with some corresponding defect or disease of the other. There is also a greater similarity between the sensations of both these, than between those of any other two senses; and hence it is, that we can sometimes tell the taste of an object from its smell, and vice versa. Hence also the reason why we apply the same epithets to the names of both these classes of sensations; as a sweet smell or taste.

It deserves also to be remarked, that both these senses seem subservient to the preservation of the animal existence, rather than to any other purpose. They accordingly constitute an object of the natural history of man, rather than of intellectual or of moral philosophy. The other three senses, on the contrary, seem rather intended for, as they certainly are essential to, our intellectual improvement, and become, of course, a proper object of investigation in the sciences of moral philosophy, or metaphysics.

The advantages derived by man and the other animals from the sense of smelling are not confined to the assistance which it affords them in the choice of their food. Most bodies in nature, when exposed to the open air, are constantly sending forth emanations or effluvia of such extreme minuteness as to be perfectly invisible. These diffuse themselves through the air, and however noxious or salutary, would not be perceived without the sense of smelling, which, if not vitiated by unnatural habits, is not only a faithful monitor when danger is at hand, but conveys to us likewise the most exquisite pleasures. The fragrance of a rose, and of many other flowers, is not only pleasant, but gives a refreshing and delightful stimulus to the whole system, while the odours proceeding from hemlock, or any noxious vegetable, or other substance, are highly offensive to our nostrils. Hence we are naturally led to seek the one class of sensations, and to avoid the other.

In some species of animals the sense of smell seems to be connected with certain mental sympathies, as those of hearing and sight are in all that possess them in any high degree; for not only their sexual desires appear to be excited by means of it, but other instinctive passions, which, according to the usual system of nature, should be still more remote from its influence. Dogs, although wholly unac- quainted with lions, will shudder at their roar; and an elephant that has never seen a tiger, will in the same manner show the strongest symptoms of horror and affright at the smell of it. "The late Lord Clive," says an ingenious writer, "exhibited a combat between two of these animals at Calcutta; but the scent of the tiger had such an effect upon the elephant, that nothing could either force or allure him to go along the road, where the cage in which the tiger was inclosed, had passed, until a gallon of arrack was given him. Upon this, his horror suddenly turning into fury, he broke down the paling to get at his enemy, and killed him without difficulty."

If riding along a road, near which a dead horse, or part of its carcass, happens to be lying, we know, that our horse although he sees it not, cannot be made to pass the place but with difficulty. Where blood has been shed, particularly that of their own species, oxen will assemble, and upon smelling it, roar and bellow, and show the most manifest signs of horror and distress; and yet these symptoms could not arise from any associated notions of danger or death, since they appear in such as never had any opportunities of acquiring them. They must therefore be instinctive like other instinctive antipathies and propensities.

But although in their mutual intercourse, animals make much use of the sense of smell, still it does not seem to be further concerned in exciting their sexual desires, than in indicating their object.

Some of those splenetic philosophers, who are ready upon all occasions to quarrel with the constitution of nature, have taken the liberty of condemning their Maker, because it has pleased his unfathomable wisdom to bestow in some instances upon the brutes senses and instincts more perfect than he has given to man, without reflecting that he has given to man an ample equivalent; for it may be asked with the poet,

Is not his reason all these powers in one? Is Heaven unkind to man and man alone? Shall he alone, whom rational we call, Be pleased with nothing if not blessed with all?

With respect to that unknown peculiarity of bodies, which is the cause of our sensations of smell, the opinions of philosophers have been very various. Until of late, the doctrine of Des Cartes and Locke on this subject was pretty generally received; but, since the publication of Dr. Reid's works, his opinion, which we deem the most correct and satisfactory, has become very popular. We will endeavour to abridge his account of this matter. For this purpose, let us suppose a person, who has grown up without the sense of smell, to be immediately endowed with the use of this organ, and placed near some flowers of an exquisite savour. When he examines what he feels in such a situation, he can find no resemblance between this new sensation, and anything with which he is already acquainted. He finds himself unable to explain its nature, and cannot ascribe to it figure, extension, or any known property of matter. It is a simple affection, or feeling of mind, and, considered abstractedly, can have no necessary connection with the nerves, the nostrils, or effluvia, or with any thing material whatever. By the nature of his constitution he is however led to refer this peculiar sensation to the nostrils, as its organ; and when, from experience, and by means of touch, he learns that external objects have the power of exciting this sensation, he concludes, that there must exist in bodies some unknown cause by which it is excited. In the first part of this process he considers the feeling, or sensation, abstractedly. As such, it exists in the mind only; and cannot exist there but when the mind is conscious of it. His consciousness soon enables him to distinguish different sorts of smells, all of them very distinct from one another, but, conformably to the nature of all sensation, extremely simple. He concludes, that each of these must have a distinct cause; and finding, by experience, that this cause is an unknown something in bodies, he concludes, that it must be a property of matter, and, for want of another, gives it the Smelling-name of smell. When he removes an odorous body from the organ, the sensation vanishes; when the body is again applied, the sensation is excited; and hence it is, that he is led naturally to connect the sensation with this unknown peculiarity of bodies by which it is produced. But since we see, that the sensation is, in a great degree, related to other objects besides its unknown cause, to the mind in which it exists, for instance, and to the organ which is its instrument, it may be asked why it becomes associated in the mind with its cause only? The reason seems pretty obvious. No single sensation, or class of sensations, is more connected with the mind, than any other of which it is susceptible. Nor is the connection subsisting between the organ and any of the sensations peculiar to it, greater than that which subsists between it and every other sensation of which it is the inlet. Hence the connection between the smell of an orange and the mind, or between it and the nostrils, is very general, and cannot, in the former instance, distinguish it from any other sensation of whatever kind, nor, in the latter, from any other particular smell. But the connection between this sensation and the orange is peculiar and permanent; and we accordingly find them always associated in the mind, just as we associate the notion of fire with the sensation of burning. The relation which a sensation of smell, or any sensation, bears to the mind, to an organ, or to the memory and conception of itself, is common to all sensations. The relation which any sensation bears to its own cause, suppose of the sensation of smell to a particular virtue or quality of bodies, is common to it with every other sensation, when considered with respect to its peculiar cause. And finally, a sensation of any kind bears the same sort of relation to the memory and conception of itself, that any other feeling or operation of mind bears to the conception and memory of that particular feeling or operation.

Whatever then be the nature of the minute particles of bodies by which our sensations of smell are excited, we cannot help considering their unknown cause as a virtue or quality of matter. Like all other modifications of material substance, it must be confessed, that this can have no resemblance to the sensations of mind. But we are not therefore to conclude with the followers of Des Cartes and Locke, that this secondary quality is a mere sensation; especially as we can readily conceive it existing where it is not smelled, or even after supposing the annihilation of every sentient being throughout the universe. The existence of the sensation we know to be momentary and fugitive; but in the existence of its cause we can, without difficulty or inconsistency, conceive a permanency independent of mind and of its sensations.

The doctrine which we have been illustrating has of late been called in question by a sceptical writer, who, it appears to us, has upon this occasion been entirely deficient in his accustomed acuteness. Dr. Reid's speculations seem so full, so clear and convincing, that we are at a loss to conceive how his meaning can be misunderstood; and yet the argument and objections of the writer to whom we allude, derive all their plausibility from a misinterpretation of Dr. Reid's meaning; and from a deviation from the established use of language. "An eminent metaphysician," says this author, "has declared that he has not the least difficulty in conceiving the air perfumed with aromatic odours in the deserts of Arabia; and he has decided, that the man who maintains smells to exist only in the mind must be mad, or must abuse language and disgrace philosophy. There are some authors, nevertheless, who differ widely on this subject from the learned metaphysician. Is it possible for a sensation to exist where there is no sentient? The authors to whom I allude think it impossible." And so, we may tell this learned author, does Dr. Reid, if he will take his word for it. Of the sensation of smell he remarks, "It Smelling is indeed impossible, that it can be in any body; it is a sensation, and a sensation can be in a sentient thing only.

Again, "I can think of the smell of a rose when I do not smell it; and it is possible that when I think of it, there is no rose anywhere existing; but, when I smell it, I am necessarily determined to believe that the sensation really exists. This is common to all sensations, that, as they cannot exist but in being perceived, so they cannot be perceived but they must exist."

But, continues this acute metaphysician, "a smell is nothing else than a sensation. It is a feeling, which may be agreeable or disagreeable; which may, as some think, be excited by various combinations of elements; but which, since it is a feeling, cannot be those elements which are said to cause it, and cannot exist where there is no creature to perceive it. What is to be understood, in philosophical strictness, by the perfumes of the desert? We can excuse the poet when he makes the ocean smile, the winds dance, and the flowers respire; or even were he to perfume the desert. But the philosopher is no such magician, and had better not wander through the regions of fancy in search of sensations where there is no sentient."

And is it then true that the word smell means only a sensation? A sensation is no more than an effect; it is a transient modification of the mind, which the mind itself can never produce. It must then have some cause which is external to the mind. Now, it is to this cause, and not to the sensation, that the name smell is most frequently applied in all languages; and it is this cause which Dr. Reid supposes capable of existing in the deserts of Arabia, where there is no sentient being to perceive it. But let us hear himself: "We have considered smell as signifying a sensation, feeling, or impression upon the mind; and in this sense it can only be in a mind or sentient being; but it is evident that mankind give the name of smell much more frequently to something which they conceive to be external, and to be a quality of body; they understand by it something which does not at all infer a mind, and have not the least difficulty in conceiving the air perfumed with aromatic odours in the deserts of Arabia, or some uninhabited island where the human foot never trod."

The faculty of smelling is something very different from the actual sensation of smelling; for the faculty may remain when we have no sensation. And the mind is no less different from the faculty, for it continues the same individual being when the faculty is lost. What is smell in the rose? It is a quality or virtue of the rose, or of something proceeding from it, which we perceive by the sense of smelling; and this is all we know of the matter. But what is smelling? It is an act of the mind, but is never imagined to be a quality of the mind. Again, the sensation of smelling is conceived to infer necessarily a mind or sentient being; but smell in the rose infers no such thing. We say, this body smells sweet, and that stinks; but we do not say, this mind smells sweet, and that stinks; therefore smell in the rose, and the sensation which it causes, are not conceived, even by the vulgar, to be things of the same kind, although they have the same name.

There are some other remarks on Dr. Reid's opinion, in the work upon which we have been commenting, which we shall pass by; we may however notice the author's concluding argument. After mentioning some examples, he observes, "Now, in these instances, we see men and animals, that must have perception of smell, if I may be permitted to say so, altogether different from each other. Is not smell sensation when the spaniel finds sport in the field for his master; when the shark pursues through the ocean its expected victim; and when the camel conducts the thirsty wanderer to a fountain of fresh water, across the burning sands of the Arabian desert? If no animal had the sensation of smell, there would be no odour; for aroma and oils may be thought to be material compositions, but are neither agreeable nor disagreeable feelings." If men and animals differ in their perceptions of smell, and, no doubt, difference of organization will cause them to do so, the conclusion should not be, we think, that smell is merely sensation, but that there is actually something external which is the cause of their sensations, and about which they differ. A rose put to the nostrils of a man, and then to those of a dog, may excite very different sensations; but we cannot think that the peculiarity of the rose, which excites those different sensations, varies by thus changing the position of the rose. If at table one person mistakes mutton for beef, and another thinks that it is venison, the conclusion may be, that it is neither venison nor beef; but no man in his senses can conclude that there is no meat at the table. But, "is not smell sensation when the spaniel finds sport in the field?"

There is sensation no doubt; but we may be permitted to ask, what would become of the spaniel's sensation of smell and of his master's sport, were there no game in the field? What of the shark's sensation of smell and pursuit, were there no victim in the ocean? and what of the camel and the thirsty wanderer, were there no fountain of fresh water in the Arabian desert? "The smell of a rose signifies two things," says Dr. Reid; "first, a sensation which can have no existence but when it is perceived, and can only be in a sentient being or mind; secondly, it signifies some power, quality, or virtue in the rose, or in effluvia proceeding from it, which hath a permanent existence independent of the mind, and which, by the constitution of nature, produces the sensation in us."

By the original constitution of our nature, we are both led to believe that there is a permanent cause of the sensation, and prompted to seek after it; and experience determines us to place it in the rose. The names of all smells, tastes, sounds, as well as heat and cold, have a like ambiguity in all languages; but it deserves our attention, that these names are but rarely, in common language, used to signify the sensations; for the most part, they signify the external qualities which are indicated by the sensations.

We have been induced thus to discuss this topic at some length, because we regretted to see Dr. Reid's opinion and reasoning misrepresented; and we shall now conclude, not as this modern Berkeleyan does, "that if no animal had the sensation of smell, there would be no odour," but, that if there were no odour or external cause of smell, no animal would have this sensation.

SMELTING IRON BY HOT-BLAST. Since the article on Recent Manufacture of Iron was published in the usual order of the progress of this work, certain changes have been introduced in the process of making iron, of so extensive and important a character, that we cannot consider them in any other light than as effecting an entire revolution in those branches of industry and of commerce connected with the manufacture and application of that most valuable of metals. The change has been comparatively unnoticed, extending itself during the last ten years, from the little spot in a remote part of this island whence it took its origin, and has now found its way over a great part of the old world, and been adopted extensively in the new. Wherever it has found its way, wealth and prosperity have attended it, poverty and sterility have fled before it; and there have been opened up vast stores of mineral wealth to assist in the advancement of civilization and industry, which our former impotence and want of skill had marked with the stigma of utter unproductiveness. It is therefore necessary that we give in this article, as supplementary to our former treatise, an account of the new process, now well known over the whole manufacturing world as the hot-blast process for smelting iron. The hot-blast process was invented in Scotland by Mr. James Beaumont Neilson, a practical engineer at Glasgow, and was by him made the subject of a patent, dated September 1828, being entitled, an "improved application of air to produce heat in fires, forges, and furnaces, where bellows and other blowing apparatus are required."

The invention of Mr. Neilson, like a great many other inventions, and indeed some of the most valuable, is characterized by extreme simplicity; and his invention so perfectly accords with all the known laws of physics, that we at once apply to it the well known exclamation of wonder, "how strange! that a thing so obvious should not have been done long before!" an exclamation in which we too often find ourselves doing an act of injustice to the very inventors to whom we lie under the weightiest obligations. Mr. Neilson's hot blast is as simple a contrivance as was the steam-engine condenser of his countryman, Mr. Watt, and indeed bears a very close analogy to its character as an invention.

Before the time of Mr. Watt, steam was introduced into that part of the steam-engine where it performed its labour, and was then condensed into water in the same place where it had done its duty, thereby causing great waste of fuel and loss of power; and to remedy this defect, Watt introduced his new principle on which his fame rests; he used a separate condenser, that is, cooled the steam, and reconverted it into water, not in the cylinder, where it was detrimental, but in a separate vessel communicating with it.

In like manner, Mr. Neilson's invention consists in separately heating that which was formerly done so as to be injurious to the process intended. Cold air was blown into a furnace designed to produce intense heat for the smelting of iron from ore, so that the cold blast of air itself required to be heated by the fuel in the furnace intended to smelt the iron, and so its temperature was cooled down by the very intensity of the blast required for the desired combustion. To remedy this defect, Mr. Neilson introduced his new principle of hot blast; and instead of allowing this blast of cold air to enter at once from the blowing-machine or bellows into the furnace, to be heated there, he provided a separate heating apparatus, by which the air of the blast was to be heated by a separate furnace and fire, previously to its entrance into the smelting furnace. This is the whole invention. A hot blast of air, instead of a cold one, is thus introduced for the generation of heat. Could anything be more simple, more natural, more appropriate, or more likely to prove effectual? This is the hot blast, which has already in this and other countries created many millions of valuable property out of what was formerly worthless, because unavailable by any of the processes formerly known.

Like most other inventions, the progress of this was at first very slow. Retarded by practical difficulties, which beset all new processes in their first use, by men who have everything to learn,—stopped every now and then by the prejudices of custom and ignorance, which cling with inveterate tenacity to maxims of established practice, and repel equally the innovations which improve and those which merely alter without improvement,—opposed also by the change of interests which such a revolution must necessarily involve; the invention, tardy in its first steps, and feeble in its early efforts, was more than once at the point of being altogether abandoned. Like the invention of Watt, a great part of the interest in its possible remuneration was transferred by the inventor to strangers, whose combined efforts and influence it was necessary to obtain on the side of the innovation. To Mr. Dunlop of Clyde iron-works Mr. Neilson had to give up three-tenths of his patent rights; to Mr. Mackintosh three-tenths; and one-tenth to Mr. Wilson of Dundivan, retaining to himself only three-tenths of this valuable monopoly. But the transfer was judicious; it was necessary. Mr. Mackintosh is distinguished as a man of much practical science; Mr. Dunlop was one of the most sagacious iron-masters of his time; and Mr. Wilson was a man of tried practical talent. The co-operation of these gentlemen was essential to the speedy and successful trial of the novel though simple process.

The following is the specification of Mr. Neilson's patent: "I, James Beaumont Neilson, do hereby declare that the nature of my said invention for the improved application of air to produce heat in fires, forges, and furnaces, where bellows or other blowing apparatus are required, and tent, the manner in which the same is to be performed are particularly described and ascertained as follows: That is to say, a blast or current of air must be produced by bellows or other blowing apparatus in the ordinary way, to which mode of producing the blast or current of air this patent is not intended to extend. The blast or current of air so produced is to be passed from the bellows or blowing apparatus into an air vessel or receptacle, made sufficiently strong to endure the blast, and through and from that vessel or receptacle, by means of a tube, pipe, or aperture into the fire, forge, or furnace. The air vessel or receptacle must be air-tight, or nearly so, except the apertures for the admission and emission of the air; and at the commencement, and during the continuance of the blast, it must be kept artificially heated to a considerable temperature.

"It is better that the temperature be kept to a red heat, or nearly so; but so high a temperature is not absolutely necessary to produce a beneficial effect. The air-vessel or receptacle may be conveniently made of iron; but as the effect does not depend upon the nature of the material, other metals or convenient materials may be used. The size of the air vessel must depend upon the blast, and on the heat necessary to be produced. For an ordinary smith's fire or forge, an air vessel or receptacle, capable of containing 1200 cubic inches, will be of proper dimensions; and for a cupola of the usual size for cast-iron founders, an air-vessel capable of containing 10,000 cubic inches will be of a proper size. For fires, forges, or furnaces, upon a greater scale, such as blast-furnaces for smelting iron, and large cast-iron founders' cupolas, air-vessels of proportionably increased dimensions and numbers are to be employed. The form or shape of the vessel or receptacle is immaterial to the effect, and may be adapted to the local circumstances or situation. The air-vessel may generally be conveniently heated by a fire, distinct from the fire to be affected by the blast or current of air, and generally it will be better that the air-vessels and the fire by which it is heated should be inclosed in brick-work or masonry, through which the pipes or tubes connected with the air-vessel should pass. The manner of applying the heat to the air-vessel is, however, immaterial to the effect if it be kept at a proper temperature. In witness whereof, I, the said James Beaumont Neilson, have hereunto set my hand and seal, the 28th day of February, in the year of our Lord 1829."

The only part of the process of smelting the iron which is at all affected by this novelty, is the transit of the air using the from the blowing machinery into the smelting furnace. The bellows, steam-engine, water-wheel, blowing cylinders, equalizing reservoirs, or other apparatus of whatever sort, for producing the current of air to blow the fire, are left unchanged, as we have already described and figured them in our article on Iron. The furnace may be left of its former shape and dimensions in every respect as used in the old process, and as we formerly described them; all that is required for the introduction of the new process, is to interpose between the smelting furnace and the blowing machinery an even, heated by a separate fire, through which, in appropriately shaped vessels or pipes, the blast of air on its way to the furnace may be heated to a considerable temperature,—400°, 600°, or any temperature found most suitable to the purpose, and so blown upon the incandescent fuel in the furnace in a hot blast, as distinguished from the ordinary cold blast of atmospheric air.

The consequences of this hot blast system in an econo- Smelting by hot-blast.

Advantages of the hot-blast system.

In a given furnace in Scotland, previous to the introduction of the new process, the following was the average result obtained:

- 20 tons of coal (coked), with 3½ tons of limestone, smelted 4½ tons of iron, being 3½ tons of fuel to each ton of iron.

In the same furnace, by the introduction of the new process, the result was as follows:

- 14 tons of coal (raw), with 2½ tons of lime, smelted 8 tons of iron, being 1½ tons of fuel to each ton of iron.

Here, then, we see that, in the first place, one half of the fuel only is required; that coking, a very expensive process, is avoided, the coal being used raw, which was formerly impossible; and that only about one-third of the quantity of limestone is required to flux the iron, and all the cost of these materials, and all the labour employed in their transport, and in the process of melting, are clearly saved. But these were not the only benefits conferred on the iron-master. The same furnace, blowing apparatus, and establishment, that formerly produced fifty tons a-week, yielded under the hot blast more than double that quantity.

As it was in Scotland that these advantages were first obtained, so it is there that they are still possessed in the highest degree. Previously to the introduction of the hot blast, it had become an almost hopeless competition to produce iron there at so cheap a rate as the Welsh iron-masters could import it into Scotland. The hot blast at once turned the scale; and Scotland now transmits annually many thousand tons of iron to all the markets of England, and even into the very heart of the iron districts of the principality itself.

The cause of this difference between the advantage which Wales has derived from the hot-blast process, and that conferred on Scotland, is simply this: the coal fields of Wales are a rich, strong, and highly carbonaceous fuel, which loses not more than thirty to forty per cent. in the process of coking. The coal basin of Scotland in the iron district is, on the contrary, of a poor, earthy, light description, so as to lose from fifty to sixty per cent. in the process of coking, and giving, for every two tons of coal, not more, and frequently much less, than one ton of coked fuel fit for the cold-blast smelting-furnace. The expense and loss in the Scottish coal by this preparatory process of coking, was therefore excessive, when compared with the Welsh coal; and hence the adoption of this new plan, which did not require this preliminary process of coking, became a much greater boon to the Scotchman, in exact proportion to his former disadvantage.

Great as these advantages have been found in Scotland, they have by no means been limited to the country of the inventor. In Staffordshire, in the wonderfully rich mineral basins of Dudley, and in Derbyshire, the invention was very early introduced, and most successfully practised. The following are the general results of the hot-blast system, as now practised in Staffordshire, in comparison with the old system:

By the cold blast,

- 8 tons of coal (coked), with 1½ ton of lime, yielded 3 tons of iron, being 2½ tons of fuel to each ton of iron.

By the hot blast, in 1840,

- 2½ tons of coal (raw), with 1½ ths of a ton of limestone, yield 2½ tons of iron, being 1 ton of fuel to each ton of iron.

The saving thus obtained in the article of fuel, is accompanied, it will be noticed, in every instance, with a corresponding saving in the limestone employed to flux the metal. But even here the whole amount of advantage does not meet the eye. It was formerly important to use the very best quality of coal that could be obtained,—light, bituminous, or earthy coal, being least fit for the purpose, and most unprofitable. Now, although it is still desirable to have a better rather than a worse fuel, the importance of this point is so greatly diminished, that almost all the inferior descriptions of poorer and more bituminous coal may be employed with economy and advantage. Lime-stone of the best quality was essential to the produce of good iron by the old method; by the new method, it is obvious, from inspection of the examples given, that the saving in limestone varies from a third to two-thirds of the quantity employed; but, in addition to this, it has become practicable to employ limestone of a very inferior quality, where better may be scarce, without sensible deterioration of the metal.

For the production of good iron, the hot-blast system has thus opened vast resources, which formerly could not be rendered available, in consequence of the inferior quality of some one of the raw materials which could be brought together in a given locality. In one place, abundant in excellent carbonate of lime and rich ore, it became impossible to realise the mineral wealth, on account of the inferior quality of the coal; while, in another, an abundant supply of good limestone, and of good coal, could not be used with advantage, from the poverty of the ore, which happened to be a clay stone, containing a small proportion of iron. Perhaps, also, a portion of sulphur mixed with the materials in such a quantity, as to ruin the iron. These all are counterbalanced by the hot blast, and every one of these impracticable cases is now exemplified in daily use.

But there is no sphere in which the hot blast has exerted a more beneficial influence in promoting the success of industry, and extending the resources of civilization, than in its application to those sterile districts of the mineral world, known as the region of the stone coal, blind coal, or anthracite formation. In the blind or stone coal strata, we have that most valuable of all combustibles, carbon, in a condition of high density and purity, amounting to as much as ninety or ninety-five per cent. of the stone coal, with a very small percentage of earthy or hydrogenous matter, yet so contracted, and, as it were, iron-bound, so hard and obdurate, that, instead of forming a good combustible, it seems to partake of the nature of that wonderful and brilliant substance, so hard of combustion as to have been reckoned one of the incombustibles until the glass of the accomplished analyst resolved the glittering brilliant into its primitive carbon. The anthracite seems, in fact, truly to deserve the name of the "black diamond," having been rendered, by its dense and close structure, nearly as incombustible. Although America, and many wide districts of Europe, abound with this rich carbon, it has failed to furnish, even in the hands of many accomplished chemists and mechanicians, an available fuel, either for the generation of steam, or for the ordinary wants of social life, and has resisted even the intense heat of the blast furnace. But even its consummate obstinacy has yielded to the power of the hot blast. In Wales, and in America, hot-blast iron of the very finest quality is now made from stone coal; and thus stores of the richest fuel which the world contains, appear only to have been reserved, by their wonderful obduracy, from the rapid destruction to which all other fuel has been so wastefully subjected, to supply the civilization and science of the nineteenth century with the means of rewarding and extending its astonishing discoveries. So kindly has Providence placed at the surface of the earth one mineral fuel to replace the forests which supplied the fires of our forefathers, and deposited another still richer, but more remote in the bowels of the earth, to await and to reward the industry and research of their children and our own. What geologist will henceforth call in question the abundance of that supply, which now seems to augment with the very means that are invented for increasing its consumption?

The Welsh coal-field is perhaps the richest in the world. Rich with bitumen on one side, it gradually falls off by insensible gradations into a more purely carbonaceous, but still free-burning coal, and, passing through every intermediate gradation, is found at last in the state of a rich, resplendent refractory anthracous, or stony coal. This, mixed in the proportion of two to three, three to two, or half and half, smelts iron readily under hot blast, and produces a rich powerful pig, possessing the qualities of a rich charcoal iron, and also capable of being converted into a most tenacious and malleable bar iron. In the anthracite district of Wales, new furnaces are rapidly rising into use; and Mr. Crane is distinguished by his extensive use of Mr. Neilson's hot-blast in that application of it.

But it is probably in America that the hot-blast system will most extensively contribute to the development of mineral wealth. The anthracite is there the staple of fuel. It covers a vast extent of country, and constitutes the only substitute with which our transatlantic brethren can replace those forests that are so rapidly receding before the advances of civilization. Here the hot-blast is most successfully employed.

We have thus given our readers the general specification of the hot-blast improvement; a specification so general as to include all possible forms of apparatus, applicable, not only to the smelting of iron, but to all cases of manufacture in which a blast is employed to produce heat, and which touches only the process of heating the air, without regard either to the mode of producing the blast, the mode of applying the blast, or the means of heating air; and the patent only provides for the carrying into effect the process of heating the air, that the blast shall be passed through a heated vessel or receptacle of any form or dimensions, such as a cast-iron retort, kept to a dull red heat of some 1000° of temperature as the most desirable. It will readily be imagined that this apparatus, described in terms of so great generality, would assume various forms, according to the different views which the various practical men employed to construct the apparatus took of the most effective mode of heating the air. This is accordingly what occurred with the progress of time, and the increasing experience of those who used the apparatus; practical difficulties gradually diminished with the increased experience which was everyday suggesting new and better expedients. It was also soon found that the advantage gained was increased in a rapid proportion with the degree of heat communicated to the air, so that the apparatus which gave at first some 300° of temperature to the air, and produced one measure of benefit, was soon superseded by a second form of apparatus giving 400°, and conferring still higher advantages; and this in its turn gave way to another and another, each giving a higher temperature to the air, and promising a higher degree of economy to the user. And thus at last a temperature between 600° and 700° was given to the air; a temperature higher than that of melting lead, which is indeed the criterion now generally applied to test the working heat of the blast.

We shall probably give our readers the clearest views of these general improvements, and of the progress which has generally taken place in carrying them into effect, by taking a single example. For this purpose we have selected the various modes of heating the air that have necessarily suggested themselves to, or been put in practice by the ingenious proprietors of the Butterly iron-works in Derbyshire, who were the first to introduce the hot-blast into that part of the country, and who have been among the most successful in carrying it into effect, and producing one of the most superior qualities of hot-blast iron.

Plate CCCXLII. fig. 1, shows the construction of the earliest and simplest plan by which the inventors of hot-blast first brought it into use. An iron vessel $h$ was formed of malleable plates, riveted together like a common steam-boiler, something near three feet in diameter, and eight or ten feet long, cylindrical, and fitted at the ends to two pipes $B$, communicating with the bellows, and $S$ with the smelting furnace. Below this large pipe or tube a fire is placed, which is fed from the door $D$, and the whole is enclosed in an oven of brickwork $O O O$, leaving a clear space all round the pipe $h$, so that the flame and hot air rising up and enveloping the receptacle, should keep it so hot as to communicate through the sides of the vessel a higher temperature to the air rushing through it, on its way from the bellows, $B$, towards the smelting furnace $S$. And in order to communicate this temperature more uniformly and completely to all the air passing through the vessel $h$, lamellar partitions $P P P$ proceeding alternately from opposite sides of the tube on its interior surface, cause the stream of air to impinge first on one side, and then on the other side of the heated iron pipe, as shown in the figure. By this apparatus a moderate current of air has been heated to three or four hundred degrees.

Fig. 2 shows the manner in which the method of heating the air was employed at first in the Butterly iron-works. In the oven $O O$ are placed the two cast-iron retorts $h$, about thirty-two inches in diameter, and nine feet long, being of metal an inch and an eighth part in thickness. They are laid parallel to each other; one of them is at one end connected with the pipe $B$, from the blowing apparatus, and this conducts the air from its other extremity through a curved junction pipe $J J$, into the second receptacle $h$; where, on its way becoming hot, it passes through the hot-air pipe $S$, from the heating furnace or oven, and is blown by the orifice $T$ through the tuyere $T$ into the hearth of the smelting furnace at $F$. In this, as is usual, more than one blast, as at $T'$, was blown into the same smelting furnace. The fire $d d$, is placed at one corner of the oven on the bars $r r$, and is fed from the door $D$, and the smoke and flame rising up and surrounding $h h$, pass through a partition by the flue $f$, and fill the second compartment of the oven, clear spaces being left quite round the retorts on every side for the communication of the heat; only at the points $k$ and $h$, they are supported by contact on the brick pillars $h$. Finally, the products of combustion pass through a flue $f$ into the short chimney $C$. In this way the cold air from the blast pipe $B$, passing into the vessel $h$, is partially heated, and is conducted into a second chamber, which, being placed immediately over the fire, is much more intensely hot, and from this second chamber at once discharged into the smelting furnace.

This apparatus was first tried in November 1830. The Its effects air was only heated to 240°. Yet so admirable is the process, that it was attended with the following effect:

With cold blast there were previously used at Butterly,

5½ tons coal (coked),

to 1 ton of iron.

By the new apparatus there were required

only 3 tons coal (raw),

to 1 ton of iron.

So admirable an effect as this was not to be neglected on account of the practical difficulties attending it, which indeed only served as an inducement to further exertion; and in about a year after the following improved apparatus, with an increased number of tubular vessels, having increased dimensions of length, was successfully introduced.

Fig. 3. In the transverse section $h h h$, are three Second ap-pipes of east-iron 1½ inch thick, being about 17 feet long, paratus, and about 22 inches in diameter. They are similarly denoted in the ground plan, and in the longitudinal section by the letters $h h h$. The cold air pipe from the blowing apparatus $B$, enters the heating oven at $b$ and traverses the pipe $h h$ to the opposite end of the furnace; here a bent pipe $h^1 h^2$ conveys the air into a second longitudinal pipe $h^3 h^4$, by which the stream of air returns back to the end of the oven at which it entered, and is conducted by a second bent pipe $h^5 h^6$ into the third tubular vessel $h^7 h^8$ in which it is for the last time exposed to the heated metal, and passes off from the heating oven into the smelting furnace, by the hot air pipe $S$, whence, as formerly, it is discharged through the twyse into the hearth of the furnace. The fuel is placed through the door $D$ upon the fire of the oven on the bars $r$, and by means of a number of small pigeon holes $c c e$, $c c e$, $c c e$, is spread over the whole length of the pipes with some measure of uniformity, whereas, if allowed to act directly on the retorts, it would irregularly and less effectually heat their surface. The manner of protecting the retorts from the direct action of the fire, is well shown in the transverse section: a brick arch $a a a$ is thrown over the fire, and the flame is only permitted to ascend through the aforesaid openings $c c e$. It will be noticed that the retorts are every where clear of the building and of each other, that they are wholly enclosed by the oven $O O O$; and it will also be seen in the transverse section, and in the longitudinal section, that the products of combustion are carried off by a descending flue $f f$, regulated by a damper $e e$, into the short vertical chimney $C$. This damper is very useful in retarding the draught of air, so as to leave the products of combustion a longer time in contact with the heaters.

This apparatus is more effective and more durable than the last. It raised the heat of the air as high as $400^\circ$ to $500^\circ$, being $200^\circ$ higher than the former plan, as indeed we should expect from the greater number and length of the vessels, and the greater surface in contact with the air. The result, compared with the last, is as follows:

By the former plan with air at $240^\circ$, 3 tons of coal were required to melt 1 ton of iron.

By the improved plan, with air at $400^\circ$ to $500^\circ$, $2\frac{1}{2}$ tons of coal were required to melt 1 ton of iron.

The reader will not fail to be struck with the fact, that a much greater gain was obtained by the original ruder plan of using the air, when compared with the old system of hot-blast, than was afterwards got from the introduction of the improved apparatus over the former one. The higher temperature does not appear to have conferred an advantage at all proportionate to the increased temperature.

Fig. 4 is a very superior and durable heating apparatus, which continues in efficient use to the present time. Its form is well adapted to prevent all the evils of expansion and contraction; and it is our opinion that by multiplying the vessels, a more effective apparatus might be made than any now in use. Its form is very ingenious, and its functions may be easily learned by studying the figure, in which the letters describe the same parts with those of the previous figures. $B$ is the pipe coming from the blowing apparatus to the heating furnace $O O O O$; $S$ is the hot air pipe, proceeding from the heating oven to the smelting furnace; $h^1 h^2$ is a large retort into which the air is at first carried, and from the further end of which a malleable iron tube $i^1 i^1$, concentric with the retort, carries it back again to that end where it first entered, and through a bent pipe $II$ conducts it along by a second interior tube $i^2 i^2$ to the further end of the second heater $h^5 h^6$, along the hot surface of which it returns in the manner shown by the arrows to the base of the second retort: now, this second retort communicates at the base with a third $h^7 h^8$, and after traversing its heated surface to the end, is brought back by a tube concentric with the axis to the base of the retort. This process might be continued with great advantage, and make one of the best series of heating vessels. The fire is covered by arches $a a a$, with small apertures $c c e$, as in the former case, to prevent the vessels from being injured by the local action of the intense fires.

This apparatus raised the temperature to between $500^\circ$ and $600^\circ$, and produced a further saving in coals. By the former plan $2\frac{1}{2}$ tons of coal were required to smelt one ton of iron. By this improved apparatus, $2\frac{1}{2}$ tons of coal melted a ton of iron.

Figs. 5 and 6 are the general forms of apparatus now most extensively used. Fig. 5 is a form first given to the apparatus, we believe, by Mr. Dixon at Calder, and hence generally called the Calder pipes. Similar pipes were also early introduced at Gartsherrie, and at Wedensbury; and are very generally approved of from their extensive heating surface, although they are liable to the inconvenience of cracking, from unequal expansion. The form, as erected at Butterly, consists of two parallel horizontal pipes L L called technically "the lying pipes," one forming a communication immediately with the cold-blast pipe B, and the other with the hot-blast pipe S. Into sockets formed in the lying pipe, are inserted a series of smaller pipes springing up at right angles with the one lying pipe, and after forming an arch, returning down to the second lying pipe, being inserted in like manner into sockets in it. The air, therefore, on entering the first lying pipe, is forced through these transverse heating pipes, or "A pipes" as they are called from their figure, and thus exposed to the heat of a very extensive surface, is delivered into the hot-air pipe. Sometimes, as at Gartsherrie and many other works, there are several times as many pipes as in this example, and the air is made to cross and recross the fire several times.

The figures of the transverse pipes are as various as the taste of the parties who use them. Sometimes they rise up and form a large semicircular arch over the fire, which is placed in the centre; sometimes a double tier of such arches is employed. Sometimes they cross the fire in the form of a pointed arch variously acuminate. Then again by some, the pipes are carried up four, six, eight, or ten feet, like columns, united at the top by a semicircular arch.

The cross section of the heating pipe is as various as the form into which the pipe itself is made to bend. A circular pipe was used at first, then a flattened elliptical one for the purpose of exposing more surface in proportion to volume; next a pipe, flat at one part, and semicircular on the other, was introduced; next a pipe of a cardoid or heart-like section was employed. At Butterly Mr. Terrop used a circular pipe cast with a solid core, to keep the air near the hot surface, as shown in the figure; and finally, he employed the rectangular section as shown in our figure 6th. All of these appear to answer their purpose of heating the air sufficiently well, and all of them cause trouble and expense by cracking now and then.

The result of all these forms is to produce a hot-blast of more than $600^\circ$ temperature, and at Butterly, figs. 5 and 6 yield as follows: $2\frac{1}{2}$ tons of coal melt one ton of iron. It is found, however, at Butterly, that pigs, for the forge, require about three cwt. less of coal than this average quantity, and that No. 1 iron requires about three cwt. more than this, as we should expect.

The Scotch use less coal than the Butterly Company, principally on this account, that the former use calcined ore, of which thirty-two cwt. with seven cwt. of lime, makes a ton of iron, while at Butterly, the quantity used for a ton of iron is $2\frac{1}{2}$ tons, with a ton of lime, being $3\frac{1}{2}$ tons of materials in one case, and less than two tons in the other.

The explanation of the principles from which hot-blast derives its efficacy as the means of producing elevated temperature, is very easy and plain to any one acquainted with the elementary principles of chemistry and mechanics. All that we think it necessary to add on this subject, we shall state in the words of Mr. Babbage and Dr. Ure.

"The increased effect," says Babbage, "produced by thus heating the air is by no means an obvious result; and an analysis of its agency will lead to some curious views respecting the future application of machinery for blowing furnaces."

"Every cubic foot of atmospheric air, driven into a furnace, con..."