Neither are principles in a more restricted sense patentable, unless they are embodied in a concrete form and their application to some purpose of utility indicated. 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, Sir W. P. 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 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, after full consideration, thought that the plaintiff did not merely claim a principle, but a

machine embodying a principle. 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 by the learned judges on the bench, to which we shall draw the reader's attention. Alderson, B., said, 'The blowing-apparatus was perfectly well known; the heating of air was perfectly well known; the tuyere was perfectly well known as applicable to blast furnaces; then what he really discovered is, that it would be better to apply air heated up to red-heat, or nearly, instead of cold air. That is the principle-that is the real discovery; but in order to take out a patent, you must have an embodiment of the principle; and his embodiment of the principle is the heating of air in a separate vessel intermediately between the blowing-apparatus and the point where it enters the furnace.' Then he says, 'I do not mean to claim any shape in which it is done; it may be done in a vessel of any shape, provided only you have such a vessel of such a shape, and fire so applied as that, in the intermediate space between the blowing-apparatus and the furnace, the air arrives at the red-heat.' And again, in reply to the argument of the plaintiff's counsel that he claimed every vessel and every shape of closed vessel in which air could be heated between the blowing-apparatus and the furnace: Then I think that is a principle, if you claim every shape. If you claim a specific shape, and go to the jury and say that which the other people have adopted is a colourable imitation, then I can understand it. If you claim every shape, you claim a principle. There is no difference between a principle

to be carried into effect in claiming the principle itself. specific mode of doing it.'

any way you will, and

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The words of Lord Justice Clerk Hope, in the case of the Househill Company v. Neilson (1 W. P. C. 683), may also be cited in reference to the same point. patent cannot be taken out solely for an abstract philosophical principle-for instance, for any law of nature or any property of matter, apart from any mode of turning it to account in the practical operations of manufacture, or the business, and arts, and utilities of life. The mere discovery of such a principle is not an invention, in the patent-law sense of the term. Stating such a principle in a patent may be a promulgation of the principle, but it is no application of the principle to any practical purpose. And without that application of the principle to a practical object and end, and without the application of it to human industry or to the purposes of human enjoyment, a person cannot in the abstract appropriate a principle to himself. But a patent will be good, though the subject of the patent consists in the discovery of a great general and most comprehensive principle in science or law of nature, if that principle is by the specification applied to any special purpose, so as thereby to effectuate a practical result and benefit not previously attained. . . . It is no longer an abstract principle. It comes to be a principle turned to account to a practical object, and applied to a special result. It becomes then not an abstract principle, which means a principle considered apart from any special purpose or practical observation, but the discovery and statement of a principle for a special purpose, that is, a practical invention, a mode of carrying a principle into effect. . . . The instant that the principle, although discovered for the first time, is stated in actual application to, and as the agent of, producing

a certain specified effect, it is no longer an abstract principle; it is then clothed with the language of practical application, and receives the impress of tangible direction to the actual business of life.' 'Undoubtedly (said Eyre, C. J., in Boulton v. Bull, 2 H. Bl. 463, 1 Carp. 149) there can be no patent for a mere principle; but for a principle so far embodied and connected with corporeal substances as to be in a condition to act and to produce effects in any art, trade, mystery, or manual occupation, I think there may be a patent. . . . It is not (referring to the case before him) that the patentee has conceived an abstract notion that the consumption of steam in fire-engines may be lessened, but he has discovered a practical manner of doing it, and for that practical manner of doing it he has taken his patent. Surely this is a very different thing from taking a patent for a principle; it is not for a principle, but for a process. Again, the substance of the invention is a discovery that the condensing the steam out of the cylinder, and protecting the cylinder from the external air, and keeping it hot to the degree of steam-heat, will lessen the consumption of steam. This is no abstract principle; it is in its very statement clothed with practical application.'

Again, in the case of Neilson v. Harford (1 W. P. C. 342) Alderson, B., said, 'I take it that the distinction between a patent for a principle and a patent which can be supported is, that you must have an embodiment of the principle in some practical mode, described in the specification, of carrying the principle into actual. effect; and then you take out your patent, not for the principle, but for the mode of carrying the principle into effect. In Watt's patent, which comes the nearest to the present of any you can suggest, the real invention of Watt was, that he discovered that by condensing steam in a separate vessel, a great saving of

fuel would be effected by keeping the steam cylinder as hot as possible, and applying the cooling process to the separate vessel, and keeping it as cool as possible; whereas before, the steam was condensed in the same vessel; but then Mr. Watt carried that practically into effect by describing a mode which would effect the object. The difficulty which presses on my mind here is, that this party has taken out a patent, in substance like Watt's, for a principle, that is, the application of hot air to furnaces; but he has not practically described any mode of carrying it into effect. If he had, perhaps he might have covered all other modes as being a variation.'

Minter's patent was for an improvement in the construction of chairs, which consisted in the application of a self-adjusting leverage to the back and seat of a chair, whereby the weight on the seat acted as a counterbalance to the weight against the back. The patentee having obtained a verdict at the trial of an action for the infringement of the patent, it was contended, on a motion for a nonsuit, that the patentee had claimed a principle, and not any particular means of carrying the principle into effect. Now, to a principle per se he was not entitled; and as to the particular means adopted, the defendant had not borrowed it. The plaintiff, it was further argued, had attempted to appropriate by his specification one of the first principles in mechanics, viz. the lever. But,' said Lyndhurst, C. B., 'it is not a leverage only, but it is a self-adjusting leverage; and it is not a self-adjusting leverage only, but it is a self-adjusting leverage producing a particular effect, by means of which the weight on the seat counterbalances the pressure on the back of a chair.' And Parke, B., said, For the application of a self-adjusting leverage to a chair, cannot he patent that? He claims the combination of the two, no matter in what shape or way

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