PATENTS 355 the words "any manner of new manufacture," and judges on the bench have admitted that the exposition of the Act has gone much beyond the letter. However, it is un doubted 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 pro cesses, (4) new methods of applying a well-known object. With regard to a patent for the new application of a well-known object it may be remarked 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 without alteration as applied to the finishing of woollen fabrics. A small amount of inven tion 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 com monly 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 manu facture, or in a lowering of price appreciable in every pound of an article extensively used by the public 1 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. As to novelty, this is the rock upon which most patents split ; for, if it can be shown that other persons have used or published 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 steer ing 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 sub ject 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 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 in vention 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 ha.s 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. Even the prior discovery of an inven tion will not prevent another independent discoverer from obtaining a valid patent if the earlier inventor kept the secret to himself, the law holding that he is the " true ami first inventor " who first obtains a patent. When an invention is the joint production of more per sons 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 em ployed 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 in quired 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. The most usual prior publication fatal to a patent is a prior specification of a similar invention. But persons are allowed to obtain patents for inventions imported from abroad, if such in ventions are new within the realm, and if they acknow ledge, on the face of their applications, that the inventions are imported, not original. Such patents are now common. 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 com plete 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 ; and now the patent is not granted till the complete specification is filed. The patentee is bound to make by this instrument a full disclosure of his secret ; he must not keep anything back either wilfully 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 ; he must point out distinctly what it is that he claims as his own exclusive property, and he must take care that he claims no more than he is entitled to. Very many patents have been invalidated by a disregard of the requirements of the law, the most common fault being that the specification 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 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 an amendment, and excising the superfluous parts ; but he will not be alloAved to extend
