Dr Joseph, distinguished for his discoveries in chemistry, was born in France, on the banks of the Garonne, in the year 1728. His father was a native of Belfast, but descended from a Scottish family which had been some time settled there. Mr Black, the father, was engaged in the wine trade; and for the purpose of carrying it on, he resided chiefly at Bordeaux.

He is represented as a man of extensive information, of candid and liberal sentiments, and of amiable manners; but particularly distinguished by the strength of his attachments, and the warmth of his heart. These amiable and estimable qualities in the character of Mr Black attracted the attention, and procured the friendship and intimacy, of the discerning and benevolent Montesquieu, who was one of the presidents of the court of justice in the province while Mr Black resided at Bordeaux. Letters and fragments of correspondence between the president and Mr Black are still preserved in the family, as precious relics and memorials of the intercourse, honourable to both, which subsisted between that great man and their ancestor.

Some time before Mr Black retired from business, he sent his son Joseph, then in his twelfth year, to Belfast, on account of his education; and having completed the usual course of instruction in a grammar school, he was sent to the university of Glasgow in the year 1746. During the time he studied at that seminary, his attention seems to have been principally directed to physical science; and he became a favourite pupil of Dr Dick, then professor of natural philosophy. When Dr Black had finished the ordinary course of general study at the university, he made choice of the profession of medicine; and he directed his views to those pursuits and studies which were necessary to qualify him for that profession.

About this time Dr Cullen was appointed to the lectureship of chemistry in the university of Glasgow. Hitherto the science had only been treated as a curious, and in some respects a useful art. This great man, conscious of his own strength, and taking a wide and comprehensive view, saw the unoccupied field of philosophical chemistry expanded before him. He was satisfied that the science was susceptible of very great improvement by means of liberal inquiry and rational investigation. He was therefore determined to enter the unbeaten path, and to conduct his followers to those unexplored regions which are included in the wide range of this comprehensive and attractive science. While these views were opening in his mind, Black became the pupil of Dr Cullen; and it was perhaps to this fortunate circumstance that he was indebted for the foundation of his future reputation as a philosopher and a chemist. The liberal and extensive views of Cullen happily accorded with the enlarged habits of thought which the young philosopher had previously acquired. Dr Cullen took a deep interest in the progress of his students. He delighted in encouraging and aiding their efforts; and, therefore, perceiving the bias of Black's pursuits, soon attached him to himself. By the intercourse and intimacy which followed, Black was led into the same train of thought, and conducted into the same course of studies; he was received into a closer connection, and became a most valuable assistant in all Dr Cullen's chemical operations. The experiments of Black were frequently adduced to prove facts which were stated in the lecture, and they were considered as unexceptionable authority. Thus commenced a mutual confidence and friendship, which was highly honourable to both, and was never afterwards mentioned by Dr Black but with gratitude and respect.

In the year 1751, Dr Black went to Edinburgh to complete the course of his medical studies. There he resided in the house of his cousin-german, Mr Russell, professor of natural philosophy in that university, a gentleman of enlarged views and liberal sentiments, whose conversation and studies must have been both agreeable and profitable to his young friend.

At this time the mode of action of lithontriptic medicines, but particularly lime-water, in alleviating the pains of stone and gravel, divided the opinions of professors and practitioners. This subject became extremely interesting both to the physician and chemist. And as it is usual for the students to enter warmly into those discussions which give rise to much difference of opinion among their teachers, this subject, being quite suited to his taste, particularly attracted and interested the attention of Dr Black, who was then one of Dr Cullen's most zealous and intelligent pupils. It appears from some of his memorandums, that he at first held the opinion that the causticity of alkalis was owing to the igneous matter which they derived from quicklime. But having prosecuted his experiments on magnesia, this grand secret of nature was laid open to his view, and he was led to conclude that the acrimony of these substances was not owing to their combination with igneous particles; that it formed their peculiar property; and that they lost this property and became mild by combining with a certain portion of air, to which he gave the name of fixed air, because it was fixed or became solid in the substances into the composition of which it entered.

This grand discovery, which marks one of the most important eras of chemical science, formed the subject of his inaugural dissertation, published at the time when he was admitted to his medical degree in the university of Edinburgh. He had not availed himself of the time he had studied at Glasgow, but took the whole course prescribed by the rules of the university. This delay, it has been supposed, may have been owing to the investigation of the subject in which he had engaged not having been completed; which determined him to proceed with caution till he had established his doctrine by a train of decisive experiments.

About the time that Dr Black took his medical degree, Dr Cullen was removed to Edinburgh, which created a vacancy in the chemical chair at Glasgow. While he remained at that university, Dr Black had been a diligent and attentive student; and the discovery published in his inaugural essay had added much to his reputation. He was therefore looked up to as a person amply qualified to fill the vacant chair; and accordingly, in the year 1756, he was appointed professor of anatomy and lecturer on chemistry in the university of Glasgow. And it was perhaps fortunate for himself, fortunate for the public and Black, for science, that a situation so favourable presented itself; Dr Joseph a situation which allowed him full time to dedicate his talents to the cultivation of chemistry, which had now become his favourite science.

Along with the lectureship on chemistry, Dr Black's first appointment in the university of Glasgow was to the professorship of anatomy. But the latter branch of medical study was either not so suitable to his taste, or he did not consider himself so well qualified to be useful in it; for soon after, arrangements were made with the professor of medicine, by which the professors exchanged departments, Dr Black undertaking that of the institutes and practice of medicine.

At this time his lectures on medicine formed his chief occupation; while the perspicuity and simplicity, the caution and moderation, which he discovered in the doctrines which he delivered, gave great satisfaction. The time and attention which were occupied in these lectures, and in the medical practice in some measure necessarily connected with his situation, are supposed by some to have been the principal cause of Dr Black's having suddenly stopped short in that brilliant career on which he had at first so successfully entered. It is more probable, however, that the calm and unambitious temper which seems to have formed a striking feature of his character, and which a less friendly hand than his learned biographer might have set down as nearly allied to indolence, checked the ardour and perseverance which were necessary to excite and carry him forward in the path of research and discovery. Whatever may have been the cause, it is to be regretted that Dr Black, so conspicuous for his patient, judicious, and elegant mode of investigation, and so distinguished for the simplicity, perspicuity, and precision of his reasonings and deductions, should have contributed so little in rearing the noble superstructure of chemical science, the foundation of which he had been the means of establishing on a firm and solid basis.

The theory of the nature of quicklime, and the cause of its causticity, soon became known to the German chemists, and from them it met with strong opposition. Various mysterious doctrines at this time prevailed in the German schools concerning the peculiar nature of fire; and as the notions there entertained of the causticity of alkaline substances involved some of these doctrines, a great many objections were started to a theory which threatened to overthrow long established and favourite opinions. The most formidable opponent of the new theory was Professor Meyer of Osnaburg. All the phenomena of the causticity and mildness of lime and alkali were, according to his explanation, to be accounted for by the action of a substance of a peculiar nature, to which he gave the name of acidum pingue. This substance, which was supposed to be formed in the lime during calcination, consisted of an igneous matter in a certain state of combination with other substances. It is a matter of some surprise that Dr Black should have experienced any uneasiness on account of the opposition made to this discovery on mere hypothesis unsupported by facts or even by plausible arguments, when his own doctrine had been fully and irrefragably established by the test of decisive experiment. Nor is it less surprising that, in the course of his lectures for several years, he should have taken great pains in refuting the arguments and in combating the objections of Meyer.

Dr Black's reception at the university of Glasgow was highly flattering and encouraging. As a student he had not only done himself much credit by his successful progress in the different pursuits in which he was engaged, but he had also during his residence there conciliated, in a high degree, the attachment and affection of the professors. When he returned as a professor, he immediately became connected in the strictest friendship with Dr Adam Smith, then professor of moral philosophy in that university; and the friendship thus commenced grew stronger and stronger, and was never interrupted throughout the whole of their lives. A simplicity and sensibility, an incorruptible integrity, the strictest delicacy, and singular correctness of manners, marked the character of each of these philosophers, and firmly bound them together in the closest union.

At Glasgow Dr Black soon acquired great reputation as a professor, and became a favourite physician in that large and active city. His engaging countenance, his agreeable and attractive manners, free from all studied endeavours to please, and the kind concern he took in the cases intrusted to his care, made him a most welcome visitor in every family.

It was between the years 1759 and 1763 that he brought to maturity his speculations concerning heat, which had occupied his attention at intervals, from the very first dawn of his philosophical investigations. His discoveries in this department of science were by far the most important of all that he made, and perhaps indeed among the most valuable which appeared during the busy period of the eighteenth century. To enter fully into the nature of his investigations would be improper in this place; but the sum of them all was usually expressed by him in the following propositions.

When a solid body is converted into a fluid, there enters into it and unites with it a quantity of heat, the presence of which is not indicated by the thermometer; and this combination is the cause of the fluidity which the body assumes. On the other hand, when a fluid body is converted into a solid, a quantity of heat separates from it, the presence of which was not formerly indicated by the thermometer; and this separation is the cause of the solid form which the fluid assumes.

When a liquid body is raised to the boiling temperature, by the continued and copious application of heat, its particles suddenly attract to themselves a great quantity of heat; and by this combination their mutual relation is so changed that they no longer attract each other, but are converted into an elastic fluid like air. On the other hand, when these elastic fluids, either by condensation or by the application of cold bodies, are reconverted into liquids, they give out a vast quantity of heat, the presence of which was not formerly indicated by the thermometer.

Thus water, when converted into ice, gives out 140° of heat; ice, when converted into water, absorbs 140° of heat; and water, when converted into steam, absorbs about 1000° of heat, without becoming sensibly hotter than 210°. Philosophers had long been accustomed to consider the thermometer as the surest method of detecting heat in bodies; yet this instrument gives no indication of the 140° of heat which enter into air when it is converted into water, nor of the 1000° which combine with water when it is converted into steam. Dr Black, therefore, said that the heat is concealed (latent) in the water and steam; and he briefly expressed this fact by calling the heat in that case latent heat.

Dr Black having established this discovery by simple and decisive experiments, drew up an account of the whole investigation, and read it to a literary society which met every Friday in the faculty-room of the college, consisting of the members of the university, and several gentlemen of the city who had a relish for philosophy and literature. This was done on the 23d of April 1762, as appears by the registers. The doctrine in question was immediately applied by its author to the explanation of a vast number of natural phenomena; and in his experi- mental investigations he was greatly assisted by his two celebrated pupils, Mr Watt and Dr Irvine.

As Dr Black never published an account of his doctrine of latent heat, although he detailed it every year subsequent to 1762 in his lectures, which were frequented by men of science from all parts of Europe, it became known only through that channel; and this gave an opportunity to others to pilfer it from him piece-meal. Dr Crawford's ideas respecting the capacity of bodies for heat were originally derived from Dr Black, who first pointed out the method of investigating that subject.

The investigations of Lavoisier and Laplace concerning heat, published many years after, were obviously borrowed from Dr Black, and indeed consisted in the repetition of the very experiments which he had suggested. Yet these philosophers never mention Dr Black at all; everything in their dissertation assumes the air of entire originality; and indeed they appear to have been at great pains to prevent the opinions and discoveries of Dr Black from being known among their countrymen. But perhaps the most extraordinary proceeding was that of M. Deluc. This philosopher had expressed his admiration of Dr Black's theory of latent heat, and had offered to become his editor. Dr Black, after much entreaty, at last consented, and the proper information was in consequence communicated to M. Deluc. At last the *Idée sur la Météorologie* of that philosopher appeared, in 1788. But great was the astonishment of Dr Black and his friends when they found the doctrine claimed by Deluc as his own, and an expression of satisfaction at the knowledge which he had acquired of Dr Black's coincidence with him in opinion. M. Deluc has, in his own vindication, published an answer to this charge. See *Edinburgh Review*, No. 12, 1805.

Dr Black continued in the university of Glasgow from 1756 to 1766. In 1766 Dr Cullen was appointed professor of medicine in the university of Edinburgh, and thus a vacancy was produced in the chemical chair of that university. Dr Black was with universal consent appointed his successor; and in the new scene on which he entered his talents became more conspicuously and more extensively useful. But whilst he could not fail to be highly gratified by the great concourse of pupils which the high reputation of the medical school of Edinburgh attracted to his lectures, his mind was forcibly impressed with the importance of his duties as a teacher. This had an effect which, perhaps, was on the whole rather unfortunate. He directed his attention exclusively to his lectures, and his object was to make them so plain as to be on a level with the capacity of the most illiterate of his hearers. The improvement of the science seems to have been altogether abandoned by him. And never did any man succeed more completely. His pupils were not only instructed, but delighted. Many became his pupils merely in order to be pleased; and this contributed greatly to extend the knowledge of chemistry. It became in Edinburgh a fashionable part of the accomplishment of a gentleman.

Perhaps also the delicacy of his constitution precluded him from exertion; the slightest cold, the most trifling approach to repletion, immediately affected his chest, occasioned feverishness, and, if continued for two or three days, brought on a spitting of blood. Nothing restored him but relaxation of thought, and gentle exercise. The sedentary life to which study confined him was manifestly hurtful, and he never allowed himself to indulge in intense thinking, without finding these complaints sensibly increased.

So completely trammelled was he in this respect, that although his friends saw others disingenuous enough to avail themselves of the novelties announced by Dr Black in his lectures, and therefore repeatedly urged him to publish an account of what he had done, this remained unaccomplished to the last. Dr Black often began the task, but was so nice in his notions of the manner in which it should be executed, that the pains he took in forming a plan of the work never failed to affect his health, and oblige him to desist. Indeed he peculiarly disliked appearing as an author. His inaugural dissertation was the work of duty. His *Experiments on Magnesia, Quicklime, and other Alkaline Substances*, was necessary to put what he had indicated in his inaugural dissertations on a proper foundation. His *Observations on the more ready Freezing of Water that has been Boiled*, published in the Philosophical Transactions for 1774, was also called for; and his *Analysis of the Waters of some Boiling Springs in Iceland*, made at the request of his friend T. I. Stanley, Esq., was read to the Royal Society of Edinburgh, and published by the council. And these are the only works of his which appeared in print during his lifetime.

The aspect of Dr Black was comely and interesting. His countenance exhibited that pleasing expression of inward satisfaction, which, by putting the beholder at his ease, almost never fails to please. His manner was wholly unaffected and graceful. He was affable, and readily entered into conversation, whether serious or trivial. He was a stranger to none of the elegant accomplishments of life. He had a fine musical ear, with a voice which obeyed it in the most perfect manner; for he sang, and performed on the flute, with great taste and feeling, and could execute a plain air at sight, which many instrumental performers cannot do. Without having studied drawing, he had acquired considerable power of expression with his pencil, and seemed in this respect to have the talents of an historical painter. Figure indeed of every kind attracted his attention; even a retort, or a crucible, was to his eye an example of beauty or deformity.

He had the strongest claim to the appellation of a man of propriety and correctness. He did every thing in its proper season, and he always seemed to have leisure in store. He loved society, and felt himself beloved in it; and, throughout his whole life, he never lost a friend, except by the stroke of death.

The only apprehension he entertained was that of long-continued sickness, less, perhaps, from any selfish feeling, than from the consideration of the trouble and distress which it would occasion to attending friends; and never was this generous wish more completely gratified. On the 26th of November 1799, and in the seventy-first year of his age, he expired without any convulsion, shock, or stupor, to announce or retard the approach of death. Being at table with his usual fare, some bread, a few prunes, and a measured quantity of milk diluted with water, and having the cup in his hand when the last stroke of the pulse was given, he set it down on his knees, which were joined together, and kept it steady with his hand in the manner of a person perfectly at his ease; and in this attitude he expired without a drop being spilt, or a feature in his countenance changed, as if an experiment had been required to show to his friends the facility with which he departed. His servant opened the door to tell him that some one had left his name; but getting no answer, stepped about half-way towards him, and seeing him sitting in so easy a posture, supporting his basin of milk with one hand, he thought that he had dropt asleep, which sometimes happened after his meals. He went back and shut the door; but before he went down stairs, some anxiety which he could not account for made him return and look again at his master. Even then he was satisfied after coming pretty near, and turned to go away; but returning a second time, and going close up, he found his master a corpse. Sleep, says the poet, is the kinsman of death. Dr Black found the relationship very close indeed, and slept (we had almost said slipt) away from time to eternity, by a transition so easy as to be imperceptible even to the eye of affection.

**Black**, a well-known colour, supposed to result from the absence of light, most of the rays falling upon black substances being not reflected, but absorbed, by them.

**Black-Book of the Exchequer.** See **Exchequer**.

**Black-Books**, a name given to those which treat of necromancy, or, as some call it, necromancy. The black-book of the English monasteries was a detail of the scandalous enormities practised in religious houses, compiled by order of the visitors under King Henry VIII., to blacken these establishments, and thus hasten their dissolution.

**Black-Forest**, a forest of Germany, in Swabia, running from north to south between Ortenau, Brisgau, part of Württemberg, and the principality of Fürstenburg, towards the source of the Danube, as far as the Rhine above Basel. It is part of the ancient Hercynian forest.

**Black-Friars**, a name given to the Dominican order, who were called also predicants or preaching friars, in France, Jacobins.

**Black-Lead**, a name vulgarly applied to plumbago, and improperly so, as being liable to cause mistakes; the mineral used in the formation of pencils having no relation whatever to any ore of lead.

**Black-Mail**, a certain rate of money, corn, cattle, or other valuable, anciently paid by the inhabitants of towns in Westmoreland, Cumberland, Northumberland, and Durham, to divers persons on or near the borders, being men of name, and allied with others in those parts, known to be great robbers and plunderers, in order to be by them freed and protected from pillage. This composition with thieves, or rather the protectors and supporters of thieves, was strictly prohibited by the 43 Elizabeth, c. 13, and in point of fact seems to have been early checked in the English border counties. But, in the Highlands of Scotland, which were brought under the dominion of the law at a much later period, the exaction of black-mail from the lowland borderers continued in spite of every effort that could be made to put it down, till after the quelling of the insurrection in 1745.

Black-mail is defined by Dr Jamieson "a tax or contribution paid by heritors or tenants, for the security of their property, to those freebooters who were wont to make incursions on estates, destroying the corns, or driving away the cattle;" and such was the power of these freebooters, and so feeble was the arm of the law, that this illegal contribution received, at one time, a kind of judicial sanction. At all events, where the government could afford no protection against the *liftings* or *kerships* practised by the cearnachs and caterans, it would have been absurd to attempt, and impossible to enforce, any prohibition against the prospective composition of such felonies, which were of constant occurrence in the Highlands or on the borders. Rob Roy Macgregor, one of the most noted of these freebooters, overawed the country as late as the year 1744, and frequently robbed the Duke of Montrose's factor of the rents after they had been collected from the tenants, and before they could be conveyed to his grace's coffers. With regard to the meaning of the word, Spelman thinks that this illegal imposition received the name of black-mail from the poverty of those who were thus assessed, and as being paid in black money, not in silver; and Du Cange adopts this idea with little variation, stating that while brass money is called *blanque* or *blanche maille*, or white money, by the French, the Saxons and English denominate it *black*, in opposition to silver, which they account white money. But the more probable opinion is, that the epithet *black* is here used in a moral sense, to indicate the illegality or iniquity of the exaction. Wachter, however, defines "black-mail," *tributum pro redimenda vexa*, deriving it from the German "placken," *exarare, exagitate*, whence "baurenplacker," *rusticorum exagitatorem*; and Schilter says that "black-en" signifies *praedari*.

**Black-Monks**, a denomination given to the Benedictines, who are called in Latin *nigri monachi*, and sometimes *ordo nigrorum*, "the order of blacks."