whether the inventions of the others can be really new, while his merit, if not greater than the others in itself, is not diminished by their subsequent discoveries.

§ 371. Earliest Applicant, under English Law, the Earliest

Inventor.

Under the English law this question of priority presented no special difficulties. The date of the patent, or that of the application, has been treated as the date of the invention, and this being a matter of public record was ascertainable by simple inspection. Under this doctrine the first patentee, or applicant for a patent, was held to be the first inventor and alone entitled to the exclusive use of the invention, — a rule entirely consistent with the theory that the chief merit of the inventor consists in giving the invention to the public.

§ 372. Earliest Performer of Inventive Act, under American Law,

the Earliest Inventor.

In this country, on the other hand, the courts early adopted the view that the exercise of the inventive faculties is as true a ground for public recompense as the act of making known the invention to the world. While, therefore, the publication of the invention is here recognized as an essential part of the consideration for the patent, the courts unhesitatingly go behind it when necessity requires, in order to ascertain which one of several rival publishers is the first and true inventor.

titled to the patent, see Electric R. R. Signal Co. v. Hall Railroad Signal Co. (1881), 6 Fed. Rep. 603; Smith v. Barter (1875), 70. G. 1; Smith v. Prior (1873), 2 Sawyer, 461; 4 O. G. 633; 6 Fisher, 469; Sayles v. Hapgood (1869), 2 Bissell, 189; 3 Fisher, 632; Agawam Co. v. Jordan (1868), 7 Wall. 583; Whitely v. Swayne (1868), 7 Wall. 685; Brodie v. Ophir Silver Mining Co. (1867), 5 Sawyer, 608; 4 Fisher, 137; Teese v. Phelps (1855), 1 McAllister, 48; Allen r. Hunter (1855), 6 McLean, 303; Goodyear v. Day (1852), 2 Wall. Jr. 283; Lowell v. Lewis (1817), 1 Mason, 182; VOL. I. .34

1 Robb, 131; Woodcock v. Parker (1813), 1 Gallison, 438; 1 Robb, 37.

That where one patent antedates another for the same invention the later patentee must prove that his inventive act took place before the earlier patent, and then the earlier patentee must prove that his inventive act preceded that of the later patentee, the evidence in all cases being clear and beyond reasonable doubt, see Thayer v. Hart (1884), 22 Blatch. 229; 20 Fed. Rep. 693; 28 O. G. 542.

See also § 375 and notes, post.

The date of the patent or the application still remains the prima facie date of the invention; but when dispute arises the date of the inventive act may be investigated, and priority awarded to him by whom this act was first performed.

§ 373. Inventive Act a Continuous Act: Begins with Conception

of Idea: Ends with Reduction to Practice.

In this investigation the mental and the physical parts of the inventive act are both regarded. The inventive act begins with the conception of the idea of means; it ends with the embodiment of that idea in a practically operative art or instrument. It is thus in its nature a continuous act; the conception of the idea being sometimes instantaneous, sometimes gradual; the reduction to practice being in one case easy and rapid, in another slow and difficult. Hence it often happens that two independent inventors, performing the same inventive act, move at different rates of progress, owing to differences in their individual circumstances or their constructive skill. Though their conceptions of the idea are simultaneous, one may reduce to practice earlier than the other. Though one precedes the other in conception, the other may yet be the first to produce the complete practical invention. Here new questions present themselves, to be determined, like the former, by the reason and the justice of the law.

§ 374. Earliest Reducer, if Earliest or Contemporaneous Con

ceiver, the Earliest Inventor.

Where one of two rival inventors has reduced the idea to practice before the other has conceived the idea, the former is unquestionably the first and true inventor. Where their conceptions are simultaneous, and one precedes the other in reduction, his earlier completion of the inventive act makes him the first inventor and the proper patentee. Neither of these cases, therefore, requires special discussion. But where the one who first conceives the idea is anticipated in its reduction to practice by another and subsequent originator of the same idea, further discrimination becomes necessary, and an additional test of priority must be applied.

§ 375. Later Reducer, if Earliest Conceiver and Diligent in Re

duction, the Earliest Inventor.

The public interest requires that every valuable invention should be perfected and made available for use at the earliest practicable moment. At the same time it is conceded that the really meritorious part of the inventive act is the conception of the idea, and therefore that the first conceiver, though the last reducer, is the actual first inventor. It is the purpose of the law at once to promote the public interest and to do full justice to the first inventor; and inasmuch as the delay in his reduction must result either from his own negligence for which he ought to suffer, or from circumstances beyond his control which ought not to avail others to his injury, the rule has been established that the first conceiver of the idea of means, if diligent in reducing it to practice, is entitled to the patent, even though a subsequent conceiver should first have rendered the invention available for public use. The test of priority in all such cases is thus the diligence of the first conceiver in reducing his idea to practice. If he has been diligent he receives the patent. If he has been negligent the patent is awarded to the first reducer.2 In examining the nature of this test, it will be found convenient to consider:

I. The conception of the idea of means, its date, and evidence; and

II. Diligence in reduction to practice.

§ 375. That the conceiver, not the embodier, is the inventor, see Yoder v. Mills (1885), 26 Fed. Rep. 273; 34 O. G. 1048.

That the inventor who first conceives the idea and puts it into practical operation is entitled to the patent, see Worswick Mfg. Co. v. City of Buffalo (1884), 20 Fed. Rep. 126; 27 O. G. 1239.

2 That the negligence of the first conceiver gives to the first reducer a prior

right, see Hubel v. Dick (1886), 28 Fed. Rep. 132; 36 O. G. 939; Gill v. Scott (1883), 23 O. G. 2511.

That a mere conception, not diligently put in practical form, avails nothing against a subsequent conceiver who has perfected the invention and obtained a patent, see Pennsylvania Diamond Drill Co. v. Simpson (1886), 29 Fed. Rep. 288.

See also § 370 and notes, ante.

The conception of the invention consists in the complete performance of the mental part of the inventive act. While this in theory necessarily precedes the physical part or reduction to practice, it in fact also embraces whatever of thought and skill the inventor may have exercised in bringing the invention to that point where reduction to practice can begin. By it inventive genius, so far as it relates to this particular invention, is exhausted; all that remains to be accomplished, in order to perfect the art or instrument, belongs to the department of construction, not creation. It is thus the formation, in the mind of the inventor, of a definite and permanent idea of the complete and operative invention, as it is hereafter to be applied in practice.

§ 377. Conception must Generate an Idea of Means.

The idea thus conceived is, in the first place, an idea of means; an idea of the application of some force to its appropriate objects in such a manner as to accomplish a desired result. Until an idea of this character is developed there is no conception of an invention. To perceive an existing want; to conceive that in some way it may be supplied; even to discover what attributes an article or operation must possess in order to relieve the want, neither of these acts results in an idea of means by which the want may be removed. To apprehend the qualities of a given substance, to conclude either from reasoning or observation that it might be usefully applied to a given purpose, falls also short of the conception of an idea of means.2 The creative process of the inventor must go far

§ 377. In Carver v. Hyde (1842), 16 Peters, 513, Taney, C. J.: (519) "Now the end to be accomplished is not the subject of a patent. The invention

consists in the new and useful means of
obtaining it."

See also §§ 87-90 and notes, ante.
2 That the mere conception that a

beyond these achievements. It must not only discern the want, the possibility of its supply, and the attributes with which the article or operation that supplies it must be endowed, but it must produce the art or instrument itself ready for application to the removal of the want. It must bring into actual contact with its object the force now latent in the given substance, and thus fulfil the purpose whose possibility the inventor as yet only perceives. When the idea has reached this point it is the idea of an invention; before this it is merely an empty speculation, or a fact in nature open to the perception of all mankind.

§ 378. Conception must Generate an Idea of Practically Opera

tive Means.

This idea must, in the second place, include every essential attribute of the complete and practical invention. If anything remains to be created or devised in order to enable the instrument or art to perform its functions in the manner proposed by the inventor, his conception of the invention is not finished, nor has he brought into existence any true idea of means. Where the shape, size, material, or location of its various parts, or the nature or arrangement of its component operations, are necessary to its practical accomplishment of the purposes for which it is designed, each of these must be fully developed in, and apprehended by, the mind of the inventor, in a condition adapted to immediate embodiment in the concrete art or instrument. But matters of mere form, as distinguished from matters of substance, constitute no part of this idea. If the performance of its functions by the concrete invention is not dependent on the shape, the size, the certain substance might be useful in a certain process, but not followed by acts or words expressing the conception, cannot be regarded as the conception of an invention, see Slade v. Blair (1880), 17 O. G. 261.

That the conception that something might be done is not the conception of an invention, see Wicks v. Dubois (1877), 11 O. G. 244; Gordon v. Withington (1876), 9 O. G. 1009.

8 That to discern a want, and to experiment, or cause others to experiment, after means to supply it, but without discovering such means, is not a conception of the invention, see Bell v. Brooks (1881), 19 O. G. 290; Union Paper Collar Co. v. Van Deusen (1872), 10 Blatch. 109; 2 O. G. 361; 5 Fisher, 597.

See also § 88 and notes, ante.