Sec. IV.-Selling.

What is a sale of the patented article so as to be an infringement of the patent, needs not to be dwelt upon at great length. Though questions may be made as to what amounts to a sale, and as to the party who is to be considered the vendor, it would be a digression to go into a minute investigation of the subject in this place. Undoubtedly, the principal, who authorizes his agent to sell for his benefit, is an infringer of the patent. And so, also, is the agent, for the orders of the principal are no excuse to him for the violation of another's right.

It has already been noticed, that a sale by operation or authority of law, as in case of bankruptcy or insolvency, is not an infringement of the patentee's right, where the debtor had an assignable interest.12

Sec. V.-IDENTITY OF THING MADE, USED OR SOLD, WITH THAT PATENTED. DIfference in Form and PROPORTIONS MERELY. INFRINGEMENT OF A COMBINATION OF A PART.

The making, using or selling of a thing, is, of course, not a violation of a patent, unless it be the thing, or

12 Supra. ch. xvi.

one of the things patented. If it vary from the patented article, merely in form or proportions, but be substantially and essentially the same, it will be a violation of the patentee's right. This doctrine was directly involved in the provision of the act of 1793, by which a variation merely in form or proportions, was declared not to be a new invention, and so not patentable; that is, conversely, it is, within the meaning of the law, the same thing, and so is an infringement.

"What constitutes form, and what principle," Mr. Justice Washington remarks, "is often a nice question to decide; and upon none are the witnesses who are examined in patent cases, even those who are skilled in the particular art, more apt to disagree. It seems to me that the safest guide to accuracy in making the distinction is, first to ascertain what is the result to be obtained by the discovery; and whatever is essential to that object, independent of the mere form and proportions of the thing used for the purpose, may generally, if not universally, be considered as the principles of the invention."13

In a suit for an infringement of a patent for a carriage wheel, whereby the load was suspended at the

13 Treadwell and Watson v. Bladen, 4 Wash. C. C. R. 706. And see Dixon v. Mayor, 4 Wash. C. C. R. 68.

circumference on the top, instead of being supported, as usual, at the centre, Mr. Justice Patteson instructed the jury, that it was not enough to constitute an infringement, that the defendant had constructed a wheel on the suspension principle, because that principle might be applied in various ways; but if the jury thought it was applied in the same way, then a variation in two or three circumstances in the defendant's wheel, from the description in the plaintiff's specification, would not prevent its being an infringement."

On the subject of the infringement of a part of the rights secured by patent, Mr. Justice Story says, "Where the inventor claims several distinct and independent improvements in the same machine, and procures a patent for them in the aggregate, he is entitled to recover against any person who shall use any one of the improvements, so patented, notwithstanding there has been no violation of the other improve

A patent for a combination merely, does not, as we have seen, give the exclusive privilege of using the separate things combined," and consequently the use,

14 Jones v. Pearce, Gods. Sup. 11.

16 Moody v. Fiske, 2 Mason 112; and see Hill v. Thompson, 2 J. B. Moore, 424; Bovill v. Moore, Dav. Pat. Cas. 361.

16 Supra, and see Brunton v. Hawkes, 4 B. & Ald. 549.

making or selling of any separate parts, less than the whole combination, is not an infringement."

A patentee, having taken out a patent for the combined operation of five parts, afterwards took out a separate patent for two of them, as being an improvement on a machine patented by another patentee. Held by Washington J. that this was not taking out two patents for the same thing, one being for a combination, and the other for a part of the things combined.18 It follows, accordingly, that if the patent is for a combination merely, the use of any one or more of the things combined, but not of the whole, is not an infringement of the patent right for the combination.

17 Moody v. Fisk, 2 Mason's R. 112.

18 Treadwell and Watson v. Bladen, 4 Wash. C. C. R. 709.