146 U.S. 210
U.S.
1892
Mr. Justice Blatchford,

after stating the case as above reported, delivered the opinion of the court.

The Circuit Court truly says, in its opinion: “Manifestly the complainant received a consideration for devising and consenting to the use of an invention which was designed to be a complete, permanent structure, -which -was to cost a large sum of money, and which he knew wrould not meet the expectation of those who had employed him, unless it should prove to be in all respects a practically operative and reasonably durable one. If he had entertained any serious doubts of its adequacy for the purpose for which it was intended, it would seem that he would not have recommended it in view of the considerable sum it was to cost. At all events, he did not treat it as an experimental thing, but allowed it to be appropriated as a complete and perfect invention, fit to be used practically, and just as it was, until it should wear out, or until it should demonstrate its own unsuitableness. He turned it over to the owners without reserving any future control over it, and knowing that, except as a subordinate, he would not be permitted to iiiake any changes in it by way of experiment; and at the time he had no present expectation of making any material changes in it. He never made or suggested a change in it after it went into use, and never made an examination with a view of seeing whether it was defective, or could be improved in any particular.”

It is contended by the plaintiff that the principles recognized by this court in Elizabeth v. Pavement Co., 97 U. S. 126, establish the patentability of the plaintiff’s invention, notwithstanding its embodiment in the California Street railroad. But the Circuit Court held that the proofs in the present case did not show a use of the invention substantially for experiment, but showed such a public use of it as must defeat the patent. The court further said that the facts wrere in marked contrast with those in Elizabeth v. Pavement Co., because there the use was solely for experiment.

In Elizabeth v. Pavement Co., the original patent was granted in August, 1854 The invention dated back as early as 1847-or 1848. Nicholson, the inventor of the pavement, in question in that case, filed a caveat in the Patent Office in August, 1847,' describing the invention. He constructed a pavement,'by way of experiment, in June or July, 1848, in a street near Boston, which comprised all the peculiarities after-wards described in his patent, the experiment being successful. The pavement so put down in Boston in 1848 was publicly used for a space of six years before the patent was applied for; and it was contended that that was a public,use within the meaning of the statute. This court, speaking by Mr. Justice Bradley, said that it was perfectly clear from the evidence that Nicholson did not intend to abandon his right to a patent, he having filed a caveat in August, 1847, and having constructed the pavement in Boston by way of experiment, for the purpose of testing its qualities ; that he was a stockholder in, and treasurer of, the corporation which owned the road in Boston where the pavement was put down, and which corporation received toll for its use; and that the pavement was constructed by him at his own expense, and was placed by him there in order to see the effect upon it of heavily loaded wagons and of varied and constant use, and also to ascertain its durability and liability to decay. It was shown that he was there almost daily, examining it and its condition, and that he often walked over it, striking it with his cane. This court held that if the invention was in public use or on sale prior to two years before the application for the patent, that would be conclusive evidence of abandonment, and the patent would be void; but that the use of an invention by the inventor, or by any other person under his direction, by way of experiment and in order to bring the invention to perfection, had never been regarded as a public use of it; and it added: “ The nature of a street pavement is such that it cannot be experimented upon satisfactorily except on a highway, which is always public. When the subject of invention is a machine, it may be tested and tried in. a building, either with or without closed doors. In either case, such use is not a public use, within the'meaning of the statute, so long as the inventor is engaged, in good faith, in testing its operation. He may see cause to alter it and improve it, or not. His experiments will reveal the fact whether any and what alterations may be necessary. If durability is one of the qualities to be attained, a long period, perhaps years, may be necessary to enable the inventor to discover whether his purpose is accomplished. And though, during all that period, he may not find that any changes are necessary,'yet be may be justly said to be using bis machine only by way of experiment; and no one would say that such a use, pursued with' a bona, fide intent of testing the qualities of the machine would be a public use within the meaning of the statute. So long as he does not voluntarily allow others to make it and use it, and so long as it is not on sale for general use, he keeps the invention under his own control, and does not lose his title to a patent. It would not be necessary, in such’ a case, that the machine should be put up and used only in the inventor’s own shop or premises. He may have it put up and used in the premises of another, and the use may inure to the benefit of the owner of the establishment. Still, if used under the surveillance of the inventor, and for the purpose of enabling him to test the machine, and ascertain whether it will answer the purpose intended, and make such alterations and improvements as experience'demonstrates to be necessary, it will still be a mere experimental use, and not a public use, within the meaning of the statute. Whilst th¿ supposed machine is in such experimental use, the public may be incidentally deriving a benefit from it. If it be a grist-mill, or a carding-machine, customers from the surrounding country may enjoy the use of it by having their grain made into flour, or their wool into rolls, and still it will not be in public use, within the meaning of the law. But if the inventor allows his machine to be used by other persons generally, either with or without compensation, or if it is with his consent put on sale for such use, then it will be in public use and on public sale, within the meaning of the law. If, now, we apply the same principles to this case, the analogy will be seen at once. Nicholson wished to experiment on his pavement. He believed it to be a good thing, but he was not sure; and the only mode in which he could test it. was to place a specimen of it in a public roadway. He did this at his own expense, and with the consent of the owners of the road. Durability was one of the qualities to be attained. He wanted to know whether bis pavement would stand, and whether it would resist decay. Its character for durability could not be ascertained without its being subjected to use for a considerable time. He subjected it to such use, in good faith, for the simple purpose? of ascertaining whether it was what he claimed it to be. Did he do anything more than the inventor of the supposed machine might do in testing his invention ? The public had the incidental use of the pavement, it is true; but was the invention in public use, within the meaning of the statute? We think not. The proprietors of the road alone used the invention, and' used it at Nicholson’s request, by way of experiment. The only way in which they could use it was by allowing the public to pass over the pavement. Had the city of Boston, or other parties, used the invention, by laying down the pavement in other streets and places, with Nicholson’s consent and allowance, then, indeed, the invention itself 'would have been in public use, within the meaning of the law; but this was not th¿ case. Nicholson did not sell it, nor allow others to use it or sell it. He did not let it go beyond his control. He did nothing that indicated any intent to do so. He kept it under his own eyes, and never for a moment abandoned the intent to obtain a patent for it. In this connection it is proper to make another remark. It is not a public knowledge of his invention that precludes the inventor from obtaining a patent for it, but a public use or sale of it. In England, formerly, as well as under our Patent Act of 1798, if an inventor did not keep his invention secret; if a knowledge of it became public before his application for a patent, he could not obtain one'. To be patentable, an invention must not have been known or used before the application ; but this has not been the law of this country since the passage of the act of 1886, and it has been very much qualified in England. Lewis v. Marling, 10 B. & C. 22. Therefore, if it were true that during the whole period in which the 'pavement was used, the public knew, how it was constructed, it would make no difference in the result. It is sometimes said that an inventor acquires an undue advantage over the public by' delaying to take out a patent, inasmuch as he thereby preserves the monopoly to himself for a longer period than is allowed by the policy of the law ; but this cannot be said with justice when the delay is occasioned by a Iona fide effort to bring his invention to perfection, or to ascertain whether it will answer the purpose intended. His monopoly only continues for the allotted period, in any event; and it is the interest of the public, as well as himself, that the invention should be perfect and properly tested, before a patent is granted for it,. Any attempt to use it for a profit, and not by way of experiment, for a longer period than two years before the application, would deprive the inventor of his right to a patent.”

"We think that the present case does not fall within the principles laid down in Elizabeth v. Pavement Co. The plaintiff did not file a caveat, and there is no evidence that he did not intend to abandon his right to a patent.. It does not appear .that any part of the structure was made at his own expense, or .that he put it down in order to ascertain its durability or its liability to decay, or that what he says he noticed in the spring of 1879 led him to make any further examination in that respect, or to test further' the fear which he says he had at that time, or that' what he then saw led him to think that the structure was weak or undesirable. It cannot be fairly said from the proofs that the plaintiff was engaged in good faith, from the time the road was put into operation, in testing the working of the structure he afterwards patented. He made no experiments with a view to alterations;' and we are of opinion, on the? evidence, that sufficient time elapsed to test the durability of the structure, and still permit him to apply for his patent within the two. years. He did nothing and. said, nothing which indicated that he was keeping the invention under his pwn control.

In Smith & Griggs Mfg. Co. v. Sprague, 123 U. S. 249. 256, 257, it was said, Mr.' Justice Matthews speaking for the court: “ A use by the inventor, for the purpose of testing the machine, in order by experiment to devise additional means for perfecting the success of its operation, is admissible; and where, as incidehs to such use, the product of its operation is disposed of by sile, such profit from its use does not change its character; bili where the use is mainly for the purposes of trade and profit, and the experiment is merely incidental to that, the principle and not the incident must give character to the use. The thing implied as excepted out of the prohibition of the statute is a use which may be properly characterized as substantially for purposes of experiment. - Where the substantial use is not for that purpose, but is otherwise public, and for more than two years prior to the application, it comes within the prohibition. The language of § 4886 of the Revised Statutes is that ‘any person who has invented or discovered any new and useful . . . machine . . . not in public use or on sale for more than two years prior to his application, . . . may . . . obtain a patent therefor.’ A single sale to another of such a machine as that shown to have been in use by the complainant more than two years prior to the date of his application would certainly have defeated his right to a patent; and yet, during that period in which its use by another would have defeated his right, he himself used it, for the same purpose for which it would have been used by a purchaser. Why should the similar use by himself not be counted as strongly against his rights as the use by another to whom he had sold it, unless his use was substantially with the motive and for the purpose, by further experiment, of completing the successful operation of his invention?”

In that case, Elizabeth v. Pavement Co., supra, was cited with approval, and it w7as said (p. 264): “ In considering the evidence as to the alleged prior use for more than two years of an invention, which, if established, will have the effect of invalidating the patent, and where the defence is met only by the allegation that the use was not a public use in the sense of the statute, because it was for the purpose of perfecting an incomplete invention' by tests and experiments, the proof on the part of the patentee, the period covered by the use haying been clearly established, should be full, unequivocal and convincing.” The court came to the conclusion that the patentee unduly neglected and delayed to apply for his patent, and deprived himself of the right thereto by the public use of the machine in question; and that the proof fell far short of establishing that the main purpose in view, in the use of the machine by the patentee, prior to his application, was to perfect its mechanism and improve its operation.

So, too, in Hall v. Macneale, 107 U. S. 90, 96, 97, it was contended that the use there involved was a use for experiment; but the court answered that the invention was complete, and ivas capable of producing the results sought to be accomplished; that the construction, arrangement, purpose, mode of operation and use of the mechanism involved were necessarily known to the workmen who put it into the safes, which were the articles in question; that, although the mechanism was hidden from view after the safes were completed, and it required a destruction of them to bring it into view, that was no concealment of it or use of it in secret; that it had no more concealment than was inseparable from'any legitimate use of it; and that, as to the use being experimental, it wras not shown that any attempt was made to expose the mechanism, and thus prove whether or not it was efficient.

In Egbert v. Lippmann, 104 U. S. 333, 336, the court remarked: “Whether the use of an invention is public or private, does not necessarily depend upon the number of persons to whom its use is known. If an inventor, having made his device, gives or sells it to another, to be used by the donee or vendee, without limitation or restriction, or injunction of secrecy, and it is so used, such use is public, within the meaning of the statute, even though the use and knowledge of the use may be confined to one person.”

Without examining any other of the defences raised, we are of opinion that the bill must be dismissed, for the reason stated by the Circuit Court.

Decree affirmed.