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."'15

In a suit for an infringement of a patent for a carriage wheel, whereby the load was suspended at the 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.16

On the subject of the infringement of a part of the rights secured by patent, Mr. Justice Story says,

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

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

"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 improvements. There is no doubt, that by the law of England, a party who pirates any part of the invention of the patentee, is liable in damages, notwithstanding he has not violated the whole. It may be that the decisions have turned upon the peculiar language of the English patents; for in all the precedents which I have seen, the patent gives the exclusive right of the whole invention, and prohibits all other persons, "directly and indirectly, to make, use or put in practice, the said invention, or any part of the same, &c. or in any wise to counterfeit, imitate, or resemble the same, or make, or cause to be made, any addition thereto, in subtraction from the same."""" But as no such intimation is given in the reports, I incline to believe that the doctrine stands upon the general principles of law, that he who has the exclusive right to the whole of a thing, has the same right to all the parts which the general right legally includes; that is, (in cases like the present,) to all the parts which he has invented.

17 Collier on Patents, 54, 57; Dav. Patent Cas. 27, 30.

The principal difficulty that arises, is in the application of the doctrine; and that may, in most cases, be removed, by considering the nature and extent of the patent, or rather of the thing invented and patented. Where the patent goes for the whole of a machine as a new invention, and the machine is, in its structure, substantially new, any person who pirates a part of the machine, substantially new in its structure, deprives the inventor, so far, of his exclusive right in his invention, and may, in a great measure, destroy the value of the patent. Where the tent is for several distinct improvements in an existing machine, or for an improved machine, incorporating several distinct improvements, which are clearly specified, then if a person pirates one of the improvements, he violates the exclusive right of the patentee, for the patent is as broad as the invention, and the invention covers all the improvements; and it is a wrong done to the patentee, to deprive him of his exclusive right, in any of his improvements."'13

pa

A patent for a combination, merely does not, as we have seen, give the exclusive privilege of using the separate things combined,19 and consequently the use, making or selling of any separate parts, less than the whole combination, is not an infringement.

18 Moody v. Fiske, 2 Mason 112; and see Hill v. Moore, 424; Bovill v. Moore, Dav. Pat. Cas. 361.

19

Thompson, 2 J. B.

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

This doctrine is thus laid down by Mr. Justice Story : "Where a patent is for a new combination of existing machinery or machines, and does not specify or claim any improvements or invention, except the combination, unless that combination is substantially violated, the patentee is not entitled to any remedy, although parts of the machinery are used by another, because the patent, by its terms, stands upon the combination only. In such a case, proof that the machines, or any part of their structure, existed before, forms no objection to the patent, unless the combination has existed before, for the reason, that the invention is limited to the combination. If there be different and distinct improvements constituting parts of the combination, which are specified as such in the patent and specification, and any one of them be pirated, the same rule seems to apply as in other cases, where part of an invention is pirated; for the patent then shows that the invention is not limited to the mere combination, but includes the particular improvements specified."

20

On this subject, Mr. Justice Washington, speaking of the use of the hopperboy, elevator and other machinery, for an improvement in which Evans took out a patent, asks, "Will it be seriously contended that a person may acquire a right to the exclusive

use of a machine because, when used in combination with others, a new and useful result is produced, which he could not have acquired independent of that combination? If he can, then if A were proved to be the original inventor of the hopperboy, B of the elevator, and so on as to the other machines, and had obtained patents for their respective discoveries, or chosen to abandon them to the public, the plaintiff, although it is obvious he could not have obtained separate patents for these machines, might, nevertheless, deprive the original inventors, in the first instance, and the public, in the other, of their acknowledged right to use these discoveries, by obtaining a patent for an improvement which consists in a combination of those machines to produce a new result." And he contends clearly that the patentee of the mere combination cannot thus deprive others of the use of the machine or parts combined, or, in other words, that the use of these separately is not an infringement."21

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

21 Evans v. Endon, 1 Pet. C. C. R. 343, 344, 345, 346.