monopoly is similar in principle to that conceded to authors and artists. under the name of copyright. There are persons who argue that no such privilege should be permitted; there are others who think that the most trifling exertions of the inventive faculties should be protected. The right course lies between these extremes. All civilized nations have considered it desirable to give inventors an exclusive right to their inventions for a limited period, not only as a matter of justice to individuals, but as a piece of sound policy tending to the advantage of the whole community. The monopoly is granted in the expectation that the inventor will derive some profit from it; and the hope of profit is known to be a great stimulus to invention. When an author writes a book, or an artist designs a picture, the law allows a right of property to those persons in their productions, and accompanies the recognition of this right with the power to repress infringements. If this were not so, very few persons would employ their time in writing books or creating works of art; and hardly any one will be bold enough to assert that the extinction of the race of authors and artists is to be desired. The same principle applies to inventors, who ought to have the works of their brain protected from piracy fully as much as the other classes of mental producers. By holding out to them the prospect of gain, they are induced, at a present loss of time and money, to attempt to discover improvements in the useful arts, in machinery, in manufacturing processes, &c.; and thus the interests of the community are advanced more rapidly than if such exertions had not been brought into play. Just as the rule of rewarding inventors is in theory, the practical application of it is attended with difficulty. To grant a very long term of exclusive possession would be detrimental to the public, since it would tend to stop the progress of improvement. A limited property must therefore be allowed; large enough to give the inventor an opportunity of reaping a fair reward, but not barring the way for an unreasonable period. And when this compromise has been decided on, it will be seen how difficult it may be to determine beforehand what is the real merit of an invention, and apportion the time to that merit. Hence it has been found necessary to allot one fixed period for all kinds of inventions falling within the purview of the patent laws. This regulation appears to be open to the complaint, that the most worthless and the most meritorious inventions are placed on the same footing. But it may be replied, that in the result this is of little consequence, since meritorious inventions alone obtain the patronage of the public, those which are destitute of value being neglected. Besides, if the complaint were well founded, there is here no sound argument against the policy of privileges of this nature, seeing that it is impossible to weigh beforehand one invention against another in the scale of merit, or to obtain a true standard of comparison.

Leaving the discussion of general considerations, we will now give an outline of the law affecting patent privileges in the United Kingdom. In the old times, the reigning prince considered himself entitled, as part of his prerogative, to grant privileges, in the nature of monopolies, to any one who had acquired his favour. These grants became so numerous that they were oppressive and unjust to various classes of the commonwealth; and hence, in the reign of James I., a statute was wrung from that king which declared all monopolies that were grievous and inconvenient to the subjects of the realm to be void. There was, however, a special exception from this enactment of all letters patent and grants of privilege of the "sole working or making of any manner of new manufactures which others at the time of making such letters patent and grants should not use, so they be not contrary to law, nor mischievous to the state." Upon these words hangs the whole law of letters patent for inventions. Various statutes were afterwards passed (which it would be well to consolidate into one act), and the principal of these is the Patent Law Amendment Act of 1852. These statutes, however, do not materially alter the law; it is chiefly the practice of obtaining letters patent, and their form, that are affected. The positive law has to be gathered from the numerous decisions of the courts, for patent law is for the most part "judge-made law." Of that law, as it now stands, we proceed to give an outline.

The inventions for which patents are obtained are chiefly either vendible articles formed by chemical or mechanical operations, such as cloth, alloys, vulcanized india-rubber, &c.; or machinery and apparatus, or processes. It may be remarked here, that a scientific principle cannot form the subject of a valid patent unless its application to a practical and useful end and object is shown. An abstract notion, a philosophical idea, may be extremely valuable in the realm of science, but before it is allowed to form a sound basis for a patent, the world must be shown how to apply it so as to gain therefrom some immediate material advantage. With regard to processes, the language of the statute of James has been strained to bring them within the words "any manner of new manufactures," and judges on the bench have admitted that the exposition of the act has gone much beyond the letter. However, it is undoubted law that a process is patentable; and patents are accordingly obtained for processes every day.

The principal classes of patentable inventions seem to be these:—

1. New contrivances applied to new ends. 2. New contrivances applied to old ends. 3. New combinations of old parts, whether relating to material objects or processes. 4. New methods of applying a well-known object.

We have not space to enlarge upon these rough divisions, and will only remark, with regard to a patent for the new application of a well-known object, that there must be some display of ingenuity in making the application, otherwise the patent will be invalid on the ground that the subject-matter is destitute of novelty. For example, a machine already in use as an excavator on land cannot be separately patented as an excavator under water; nor can a machine employed in the finishing of cotton goods be afterwards patented as applied to the finishing of woollen fabrics. A small amount of invention is indeed sufficient to support a patent where the utility to be derived from the result is great. A small step in advance, a slight deviation from known processes, may have been apparently brought about by the exercise of little ingenuity; but if the improvement be manifest, either as saving time or labour, a patent in respect of it will stand. The mere omission of a step from some commonly practised process has been held sufficient to support a patent for a new method of manufacture; and how often do we see what appears to be a very trifling degree of novelty, attended with very advantageous consequences, sometimes resulting in the entire revolution of a manufacture, or in a lowering of price appreciable in every pound of an article extensively used by the public.

Whatever be the nature of the invention, it must possess the incidents of utility and novelty, else any patent obtained in respect of it will be invalid. The degree of utility need not, however, be great; it is sufficient if a jury can find some utility in it. As to novelty, this is the rock upon which most patents split; for if it can be shown that other persons have used the invention before the date of the patent, it will fall to the ground, although the patentee was an independent inventor deriving his ideas from no one else. The difficulty of steering clear of this rock will be apparent at once. Suppose A, in London patents an invention the result of his own ingenuity and patient study, and it afterwards appears that B, in some distant part of the kingdom, had been previously openly using the same thing in his workshop, A's patent is good for nothing. Thus, in one of the cases which arose out of Heath's carburet of manganese patent, a patent celebrated in the law courts, it appeared that three firms had used a process in the manufacture of steel which was substantially the same as that forming the subject of the patent. They had used the process openly in the way of their trade previous to the date of the patent, although it had not become generally known. This prior use of the invention was held to deprive the patent of validity. It is therefore a very frequent subject of inquiry, whether an invention has been previously used to such an extent as to have been publicly used in the sense attached by the courts to this phrase; the more especially as, if the prior use of the invention by some other person has not been public and general, an act of Parliament (5 and 6 Will. IV., cap. 83) has given the patentee a remedy against the strict rule of law by means of a petition to the Privy Council. The inventor himself is not allowed to use his invention either in public or secretly, with a view to profit, before the date of the patent. Thus, if he manufactures an article by some new process, keeping the process an entire secret, but selling the produce, he cannot afterwards obtain a patent in respect of it. If he were allowed to do this, he might in many cases easily obtain a monopoly in his invention for a much longer period than that allowed by law.

The rule, that an inventor's use of the invention invalidates a subsequent patent, does not, however, apply to cases where the use was only by way of experiment with a view to improve or test the invention. And it has been repeatedly decided that the previous experiments of other persons, if incomplete, or abandoned before the realization of the discovery, will not have the effect of vitiating a patent. Nor will such an effect be produced by the previous discovery of the subject-matter of a patent, if the discoverer keeps the secret to himself; the law holding that he is the "true and first inventor" referred to in the statute of James, who first obtains a patent.

When an invention is the joint production of more persons than one, they must all apply for and obtain a joint patent, for a patent is rendered invalid on showing that a material part of the invention was due to some one not named therein. The mere suggestion of a workman employed by an inventor to carry out his ideas will not, however, require that he should be joined, provided that the former adds nothing substantial to the invention, but merely works out in detail the principle discovered by his employer. In certain cases in which patents taken out by the celebrated Sir Richard Arkwright came to be inquired into, it was proved that the inventions were really made by persons in Arkwright's employment. Their value being perceived by him, he adopted them, and obtained the patents in question, but under these circumstances they were adjudged invalid.

If it can be shown that the invention in respect of which a patent has been obtained was previously described in a printed book in circulation in Great Britain, whether such book be in the English or a foreign language, the patent is also invalid; because a man has no right to obtain a monopoly in that which is already a part of the stock of public information; and it is not necessary to prove that the patentee was acquainted with the book, and derived his ideas from that source.

But persons are allowed to obtain patents for inventions imported from abroad, if such inventions are new within the realm, and if they acknowledge, on the face of their petitions, that the inventions are imported, not original. Such patents are now common. If the invention has been patented abroad, the law directs that the British patent shall expire at the same time as the foreign patent.

The attributes of novelty and utility being possessed in due degree by an invention, the chief remaining difficulty with which a patent has to contend resides in the specification, the instrument by which the inventor describes the nature of the invention, and the means by which it may be carried into effect. An inventor is bound, in return for the monopoly conceded to him, to instruct the public how to work the invention when the monopoly shall have expired, and to inform them in the meantime what it is they are shut out from using. The patentee may either file this instrument along with his petition for a patent, or he may reserve it until the end of six months from the date of the patent. In either case, he must make a full disclosure of his secret; he must not keep anything back either willfully or accidentally; he must render everything plain and clear, showing no attempt to mislead, and leaving nothing ambiguous; he must distinguish what is old from what is new, and take care that he claims no more than he is entitled to; in short, the invention must be accurately and intelligibly described, properly limited, and communicated to the public in such a way that they may have a complete knowledge of that in which they are granting to him a temporary monopoly. Very many patents have been invalidated by inattention to these rules in framing the specification,—the most common fault being, that it claims too much; in other words, it claims something that is already public property, or another man's patented invention. And here we are brought back again to the question of novelty.

If a patentee discovers that his specification claims more than he is entitled to, he may put the matter right by filing a disclaimer, and excising the superfluous parts; but he will not be allowed to extend his claims in any degree. He may cut out anything, but he can insert nothing.

The term for which a patent is originally granted is fourteen years, but the Crown has power, under an act of Parliament (5 and 6 Will. IV., c. 83), and on the report of the Judicial Committee of the Privy Council, before which the proceedings to this end take place, to extend the time of a patent from its expiration for any additional time not longer than fourteen years. But an extension will only be granted on the patentee showing that he has not been adequately rewarded; and what is adequate reward depends on the special circumstances of each case.

Patent privileges, like most other rights, can be made the subject of sale. Partial interests can also be carved out of them by means of licenses, instruments which empower other persons to exercise the invention, either universally, and for the full time of the patent (when they are tantamount to an assignment of the patentee's entire rights), or for a limited time, and within a limited district. By an exclusive license is meant one that restrains the patentee from granting other licenses to any one else. By means of a license a patentee may derive benefit from his patent without entering into trade, and without running the risks of a partnership.

A patentee's remedy for an infringement of his rights is by civil suit, there being no criminal proceeding in such a case. In prosecuting such suit, he subjects those rights to a searching examination, for the alleged infringer is at liberty to show that the invention is not new, that the patentee is not the true and first inventor, &c., as well as to prove that the alleged infringement is not really an infringement. But it may here be remarked, that a patentee is not bound down (unless he chooses so to be) to the precise mode of carrying the invention into effect described in the specification. If the principle is new, it is not to be expected that he can describe every mode of working it; he will sufficiently secure the principle by giving some illustrations of it; and no person will be permitted to adopt some mode of carrying the same principle into effect, on the ground that such mode has not been described by the patentee. On the other hand, when the principle is not new, a patentee can only secure the particular method which he has invented, and other persons may safely use other methods of effecting the same object. Instances of this occur every day; and it is well known that scores of patents have been taken out for screw-propellers, steam-hammers, water-meters, &c., each of which is limited to the particular construction described, and cannot be extended farther. Again, where the invention patented consists of a combination of parts, some old and some new, the whole constituting a new machine or a new process, it is not open to the world to copy the new part and reject the rest. A man is not suffered to allege that the patent is for a combination, and that the combination not having been used, there has been no infringement.

The Crown has power to repeal any letters patent on good grounds being shown by means of a writ of seire facias; and this is issuable at the request of any subject. Want of novelty in the invention, the fact of the patentee not being the inventor, and the insufficiency of the specification, form good grounds for repealing a patent.

Patents are not now extended to the colonies, and such of our colonies as possess a legislature are gradually acquiring patent laws for themselves.

The patent business of the United Kingdom is carried on under the direction of commissioners appointed by the act of 1852, the chief of whom is the lord chancellor; and the whole of it is transacted at one office in London, instead of at many offices, as formerly. Previous to that act, a separate patent was issued for each of the three kingdoms, but now one patent is valid throughout the realm. The proceedings taken with a view to obtain a patent commence with the presentation of a petition, accompanied by a sketch of the invention and a declaration of its originality. Various steps are interposed before the patent is issued, in order to afford those who have grounds for opposing the grant an opportunity of doing so. Most patents are obtained through persons styled patent agents, who devote themselves to this branch of business. The act just referred to introduced various useful reforms in the proceedings for obtaining patents, but greater simplicity and a lessening of the expense are still desirable.

(For further information on the subject of this article, the reader is referred to Johnson's Patentee's Manual, second edition, 1858, as comprising an exposition of the law and practice within a moderate compass.) (J.Y.J.)a broad flat dish, or libation-saucer, among the Romans, deriving its name, according to Macrobius (Sat. v. 21), from its open, shallow form ("plannum ac patens est"). The ordinary paterae were made of common red earthenware, slightly ornamented; but the more valuable vessels of this class were composed for the most part of bronze, and every family of easy circumstances possessed one of silver. The original use of the patera seems to have been domestic, which gave origin, in all likelihood, to its employment at sacrifices. Numerous specimens of paterae are to be seen in almost all collections of ancient fictile vases, and especially in the British Museum.