all letters patent and grants of privilege of the sole working or making of any manner of new manufactures to the true and first inventor of such manufacture, 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, by raising prices of commodities at home, or hurt of trade, or generally inconvenient. It was afterwards declared that these excepted grants of privilege should have the same validity that they had previous to the passing of the statute, but no other. Hence, when the validity of a monopoly comes into question, the first point to con

sider is, whether it is rendered void by the statute; and secondly, if it should not be thereby avoided, whether it is a privilege permitted by the common law.

In this treatise, however, we restrict ourselves to a consideration of Letters Patent for inventions. It is not every kind of discovery that can be protected by letters patent. For example, no valid patent could be obtained for a new game of skill or chance; or for a new method of calculation; or for a newly-discovered grain suitable for food; or for a newly-discovered natural substance suitable for manure, such as guano, or mineral phosphate of lime. These would not be inventions within the meaning of the statute of James I. and the decisions of our courts of law, which require a patentable invention to be referable to some manner of manufacture, in addition to the possession of the qualities of utility and novelty.

Nor is it every one who may succeed in obtaining from the Crown a grant of letters patent for an invention that is able to sustain it in a court of law. Letters patent are only valid in the hands of the first and true inventor (the language of the statute of James), or in the hands of those who have duly succeeded to his rights.

Again, a patent privilege cannot be granted in perpetuum; it must not endure for more than a limited number of years.

We shall take these things in order, and shall proceed to inquire in the following chapters

1. What is the subject-matter or nature of a patentable invention, and what are the incidents that must by law accompany it.

2. To whom patent privileges may legally be granted. 3. What is the possible duration of such privileges, and the territory over which they may extend.

These matters being disposed of, there will still remain for consideration the very important topic of a Specification-the document which the law requires every patentee to draw up and make public before or soon after he obtains his letters patent. Chapters on some collateral subjects, such as Oppositions to the grant of letters patent, Disclaimers, the Assignments of letters patent, their Prolongation, and the Infringement of patent rights, will then close this treatise.

In the Appendix will be found a reprint of all the Acts of Parliament relating to Letters Patent, with the Rules, Regulations, and Forms, and an outline of the Patent Laws of Foreign Countries and British Colonies.

5

CHAPTER II.

THE SUBJECT-MATTER OR NATURE OF A PATENTABLE INVENTION. NO PATENT FOR A BARE PRINCIPLE.-PROCESSES. -CLASSES OF INVENTIONS. AMOUNT OF INVENTION. SECOND PATENTS.

IN proceeding to consider the subject-matter or nature of the inventions which may legally be made the subject of patent privileges, it is proper to premise that no general definition can be given which shall exactly mark out what can and what cannot be included in a valid patent. Where the invention is not one of a well-known class, it will be much better for the inventor to consult some one conversant with such matters, some one whose practical experience comes in aid of general principles, and who is bound by his profession and standing in society to the utmost secrecy, -than to rely altogether upon what is stated in books, or upon a narrow range of precedent. It is the more important that the inventor's attention should be drawn to this point previous to his incurring expense, since a patent is taken out entirely at the risk of the inventor, the Crown in no degree guaranteeing the validity of its grant, which, if contested, must be judged by the abstract rules of law applicable to the case.

We believe it will be found, on examination of the cases, that the inventions which have received the sanction of judicial decision may be classed under one or other of the following heads:

1. Vendible articles, the result of chemical or mechanical processes, such as medicines, felt, waterproof cloth, etc.

2. Machines, or improvements in machines.

3. Processes, in some cases requiring, in others not requiring, special machinery.

We need not at present enter into further detail as to the inventions which fall under the first two heads; but with regard to those comprehended under the third head, we shall make some remarks, after disposing of the cases relating to scientific principles, or the laws of nature.

It has been repeatedly laid down by the Courts that

BARE PRINCIPLES ARE NOT PATENTABLE.

A principle may be of the utmost value in the eyes of philosophers; its discovery may lead to highly important consequences, and form the germ of a striking advance in civilization; yet unless its discoverer can show at least one application of it to a useful purpose, -unless he can point out the means of gaining therefrom some immediate material advantage, he is not permitted to exclude his fellow-subjects from turning it to any account they like. "I rather think it would be difficult" (said Lord Kenyon, in Hornblower v. Boulton, 8 T. R. 95; Dav. Pat. Ca. 221) "to form a specification of a philosophical principle; it would be something like an idea without a substratum."

Neither are principles in a more restricted sense patentable, unless they are embodied in a concrete form by showing their application to one or more useful purposes. "You cannot" (said Alderson, B., in Jupe v. Pratt, 1 W. P. C. 145) “take out a patent for a principle. You may take out a patent for a principle coupled with the mode of carrying the principle into effect, provided you have not only discovered the principle, but invented some mode of carrying it into effect. But then you must start with having invented some mode of carrying the principle into effect."

Again, Page Wood, V. C., said, in Dangerfield v. Jones (13 L. T. N. s. 142), "If, having a particular purpose in view, you take the general principles of mechanics and apply one or other of them to a manufacture to which it has never been before applied, that is a sufficient ground for taking out a patent, provided that the Court sees that which has been invented is new, desirable, and for the public benefit."

In the much-debated case of Neilson v. Harford (1 W. P. C. 295) a great deal was said as to the point now before us. Neilson took out his patent in 1828 for the improved application of air to produce heat in furnaces, and in his specification declared that his invention consisted in passing a blast of air from the blowing-apparatus into an air-vessel kept heated to a considerable temperature, to a red-heat, or nearly so, and from that vessel, by means of a pipe, into the furnace; that the size of the vessel must depend on the blast, and on the heat necessary to be produced, but that the form of the vessel was immaterial to the effect, and might be adapted to the local circumstances or situation. The defendants, who were alleged to have infringed this patent, contended that it was void, as being for a principle. The Court of Exchequer admitted that it was very difficult to distinguish it from the specification of a patent for a principle; but after full consideration they thought that the plaintiff did not merely claim a principle, but a machine embodying a principle. They thought that the case must be considered as if the principle being well known, the plaintiff had first invented a mode of applying it by a mechanical apparatus to furnaces; and the invention then consisted in this-the interposition of a receptacle for heated air between the blowing-apparatus and the furnace. In the course of the argument, on motions subsequent to the trial, various observations were made