(s) Act 1870, § 26. See Sickles v. Gloucester Man. Co. 1 Fish. 222; Johnson p. Root, id. 351; Rich v. Lippincott, 2 Fish. 1; Dixon v. Moyer, 4 Wash. 73. "The specification," says Story, J., "has two objects; one to make known the manner of constructing the invention so as to enable artisans to make and use it, and thus give the public the full benefit of the discovery after the expiration of the patent. The other object is, to put the public in possession of what the party claims as his own invention, so as to ascertain if he claim anything that is in common use, or already known, and to guard against prejudice or injury from the use of an invention which the party may otherwise innocently suppose not to be patented. Evans v. Eaton, 7 Wheat. 434. Accordingly, if the description fails to distinguish clearly between what is new in the alleged invention and what is old, or if the terms of the patent are so obscure or doubtful that the court cannot determine what is the particular improvement claimed, the patent will be void for uncertainty. Lowell v. Lewis, 1 Mass. 188; Barrett v. Hail, id. 188; Ames v. Howard, 1 Sumn. 485; Hovey v. Stevens, 3 Wood, & M. 80; Seymour v. Osborne, 11 Wall. 541; Wintermute v. Redington, 1 Fish. 239; Langdon v. De

Groot, 1 Paine, 207. And the description must be sufficiently clear and specific to enable one skilled in the art to which the invention relates, to put it in practice without further instruction, and without the exercise of any inventive power of his own. Singer v. Walmsley, 1 Fish. 558; Wayne v. Holmes, 2 Fish. 20; Gray v. James, Pet. C. C. 401; Brooks v. Bicknell, 8 McLean, 260; Davoll v. Brown, 1 Wood, & M. 56. But old and well-known machinery with which the patented device is to be connected, need not be specifically described. Page v. Ferry,

1 Fish. 296; Emerson v. Hogg, 2 Blatchf. 9; Kneass v. Schuylkill Bank, 4 Wash 14. On the other hand, it is well settled that patents are to be construed liberally, and not to be rigidly interpreted. It is enough if the court can see what is the nature and extent of the claim by a reasonable interpretation of the language used, however imperfectly or inartificially the patentee may have expressed himself. Hogg v. Emerson, 6 How. 479; Grant v. Raymond, 6 Pet. 218; Turrill v. Mich., etc. R. R. 1 Wall. 491; Imlay v. N. ft W. R. R. 1 Fish. 340; Potter v. Holland, 1 Fish. 382; Ryan v. Goodwin, 3 Sumn. 320. And "in determining the sufficiency of the patent, the whole instrument - that is the patent, embracing the specification and drawings - is to be taken together, and, if from these the nature and extent of the claim can be perceived, the court is bound to adopt that interpretation and give it full effect." Parker v. Stiles, 5 McLean, 54; Earle v. Sawyer, 4 Mass. 1; Carver v. Braintree Man. Co

2 Story, 482; Judson v. Cope, 1 Fish. 615; Ransom v. Mayor of N. Y. 4 Blatchf. 157; Pitts v. Wemple, 2 Fish. 10.

oo fringement, which did not certainly include some essential thing which the patent certainly included because it is expressly mentioned therein.

The patent gives to the patentee the exclusive right "of making, using, and vending" the invention. It is therefore an infringement of this right, to make, or use, or vend that invention.

If the article be a machine, it is the whole machine. He only is an infringer who completes the article, and not a mechanic or laborer who makes parts of it. (u) So a sale of the materials of the machine, or of the parts, severally, is no infringement, unless it be a sale of the parts, severed from each other, and in succession, with intent that the purchaser shall put them together and so procure the whole machine. (v) And if a sheriff sells the materials of a machine, as materials, and a purchaser buys them and puts them together to make the machine, it is he and not the officer who is responsible. And it has been held, that, when the patent is for both process and product, both being new, a sale or use of the manufactured article is itself an infringement. (w)

Generally, if the article patented is a thing produced in a particular and specified way, the patent will cover both the article and the process by which it is made, and either may be infringed.

It must always be remembered that the question whether a certain article, or product, or process, is an infringement upon another certain article, or product, or process, is the question, Are they the same or are they different? Again, it is not easy to say whether this means substantially, or essentially, the same, or precisely the same. For although a mere verbal or apparent resemblance would not suffice to constitute an infringement, yet, if the article complained of distinctly interfered with the exclusive property of the patentee as described by him, it would not be of much use to the defendant to descant upon the similarity or difference of the articles in essence or in substance. If now we oo remember * the extreme difficulty of all questions involving identity or difference, and suppose them complicated, as they often are in practice, with the metaphysical questions above suggested, we may see how impossible it must be to subject such questions to determination by a system of positive rules.

(u) Delano v. Scott, Gilpin, 498; Sargent v. Lamed, 2 Curt. 340.

(v) Sawin v. Guild, 1 Gall. 484.

(w) Goodyear v. Railroads, 2 Wall. Jr.

866; Goodyear v. N. J. Cent. R. R. 1 Fish. 626; Goodyear v. Providence Rubber Co. 2 Clif. 851.

As an illustration of this, we may refer to the role, that no one can protect his imitation of a patented article by showing that he had introduced a new mechanical principle, if this were only equivalent to those employed by the patentee. (x) But our notes will show that he would be a very acute man who could certainly discern, or a very bold man who would certainly assert, what is meant by "a mechanical equivalent."

A purchaser of a patented article may repair it as long as it will last; but must not make a new one under the pretence of repair, nor infringe on another's patent. (xx)