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says of these spurs: "I do not claim to have originated the devices known as 'spurs' or 'prongs' on the wires, they having been used before, but confine myself to the means for holding the spurs at proper intervals on the wires and to the means for attaining a uniform tension of the wires, as claimed." This disclaimer, it will be observed, is of spurs or prongs generally -not of the coiled barb either alone or in combination with the twisted wires-and is made with reference to that application only. It is true that this patent was subsequently reissued with a broadly expanded claim for a combination with a fence-wire of a barb formed of a short piece of pointed wire, secured in place upon the fence wire by coiling between its ends, forming two projecting points; but this reissue was held to be unwarranted and void in Washburn & Moen Manufacturing Company v. Fuchs, 16 Fed. Rep. 661, 667. This attempted reissue, however, did not in any way affect his original application, which stood upon its own merits, and, after being rejected and amended three times, was finally passed, with a claim substantially identical with the first claim of the original application, and the patent granted. In legal effect this was a prior patent, since the date of the application and not the date of the patent controls in determining the legal effect to be given to two patents issued at different dates to the same inventor and the order in which they are to be considered. In any event, the reissue in 1876 of one patent would not affect another patent granted in 1874.

From this review of the state of the art at the time the patent in suit was issued it is evident that Glidden can neither claim broadly the use of the plain or the twisted wire, nor the sharp thorns or barbs, nor indeed the combination of the two as they appear in the Kelly patent. It does not follow, however, that he did not make a most valuable contribution to the art of wire fencing in the introduction of the coiled barb, in combination with the twisted wire, by which it is clamped and held in position. By this device the barb was prevented from turning or moving laterally and was held rigidly in place. If this be also true of the device shown in Figure 2 of the Kelly patent of February 11, 1868, the immobility of the barb in that

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patent is due to the aid of a blow struck by a hammer, since the mere fact that the barbs were strung upon the wires would not of itself prevent a movement within certain limits unless they were held fast by compression. Indeed, it is obvious, as the patentee says, that the effect of the second wire is simply to increase the strength of the wire, and not, as in the Glidden patent, to hold the barb rigidly in place, though, of course, it would prevent its movement to any considerable extent in either direction. All he says of it in this connection is that "it tends to insure a regularity in the distribution of the points in many different directions." The vital difference in the two patents is in the shape of the barb itself. In one case a flat bit of metal is used of an elongated diamond shape, through which a hole is pierced, by means of which it is strung upon the wire, requiring something more than the aid of a second wire twisted upon the first to render it immovable. In the other the barb is a piece of wire coiled about one of the fence wires, and held rigidly in place by the twisting of another wire about the first.

It is true that the affixing of barbs to a fence-wire does not apparently give a wide scope to the ingenuity of the inventor; but from the crude device of Hunt to the perfected wire of Glidden, each patent has marked a step in the progress in the art. The difference between the Kelly fence and the Glidden fence is not a radical one, but slight as it may seem to be, it was apparently this which made the barbed-wire fence a practical and commercial success. The inventions of Hunt and Smith appear to be scarcely more than tentative, and never to have gone into general use. The sales of the Kelly patent never seem to have exceeded 3000 tons per annum, while plaintiff's manufacture and sales of the Glidden device (substituting a sharp barb for a blunt one) rose rapidly from 50 tons in 1874 to 44,000 tons in 1886, while those of its licensees in 1887 reached the enormous amount of 173,000 tons. Indeed, one who has travelled upon the western plains of this continent cannot have failed to notice the very large amount of territory enclosed by these fences which otherwise, owing to the great scarcity of wood, would have to be left unprotected.

Under such circumstances courts have not been reluctant to

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sustain a patent to the man who has taken the final step which has turned a failure into a success. In the law of patents it is the last step that wins. It may be strange that, considering the important results obtained by Kelly in his patent, it did not occur to him to substitute a coiled wire in place of the diamond shape prong, but evidently it did not; and to the man to whom it did ought not to be denied the quality of inventor. There are many instances in the reported decisions of this court where a monopoly has been sustained in favor of the last of a series of inventors, all of whom were groping to attain a certain result, which only the last one of the number seemed able to grasp. Conspicuous among these is the case of Loom Company v. Higgins, 105 U. S. 580, 591, where an improvement in looms for weaving pile fabrics, consisting of such a new combination of known devices as to give to a loom the capacity of weaving fifty yards of carpet a day, when before it could only weave forty, was held to be patentable. It was said by the court, in answer to the argument that the combination was a mere aggregation of old and well-known devices, that "this argument would be sound if the combination claimed by Webster was an obvious one for attaining the advantages proposed-one which would occur to any mechanic skilled in the art. But it is plain from the evidence, and from the very fact that it was not sooner adopted and used, that it did not, for years, occur in this light to even the most skilful persons. It may have been under their very eyes, they may almost be said to have stumbled over it; but they certainly failed to see it, to estimate its value, and to bring it into notice. Now that it has succeeded, it may seem very plain to any one that he could have done it as well. This is often the case with inventions of the greatest merit. It may be laid down as a general rule, though perhaps not an invariable one, that if a new combination and arrangement of known elements produce a new and beneficial result, never attained before, it is evidence of invention."

So in Consolidated Valve Company v. Crosby Valve Company, 113 U. S. 157, 179, it was said "that Richardson's invention brought to success what prior inventors had essayed and

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partly accomplished. He used some things which had been used before, but he added just that which was necessary to make the whole a practically valuable and economical apparatus. The fact that the known valves were not used, and the speedy and extensive adoption of Richardson's valve, are facts in harmony with the evidence that his valve contains just what the prior valves lack, and go to support the conclusion at which we have arrived on the question of novelty."

In Smith v. Goodyear Dental Vulcanite Company, 93 U. S. 486, 495, it was said by the court: "We do not say the single fact that a device has gone into general use, and has displaced other devices which had previously been employed for analo gous uses, establishes in all cases that the later device involves a patentable invention. It may, however, always be considered; and, when the other facts in the case leave the question in doubt, it is sufficient to turn the scale." See also Magowan v. New York Belting Co., 141 U. S. 332, 343.

(2) Thus far we have considered, as bearing upon the state of the art, devices, the character, construction and scope of which were exactly defined in the specifications and drawings of actual patents, the only question presented being the proper interpretation of such patents, and the bounds they had set to the ingenuity of succeeding inventors. We have now to deal with certain unpatented devices, claimed to be complete anticipations of this patent, the existence and use of which are proven only by oral testimony. In view of the unsatisfactory character of such testimony, arising from the forgetfulness of witnesses, their liability to mistakes, their proneness to recollect things as the party calling them would have them recollect them, aside from the temptation to actual perjury, courts have not only imposed upon defendants the burden of proving such devices, but have required that the proof shall be clear, satisfactory and beyond a reasonable doubt. Witnesses whose memories are prodded by the eagerness of interested parties to elicit testimony favorable to themselves are not usually to be depended upon for accurate information. The very fact, which courts as well as the public have not failed to recognize, that almost every important patent, from the

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cotton gin of Whitney to the one under consideration, has been attacked by the testimony of witnesses who imagined they had made similar discoveries long before the patentee had claimed to have invented his device, has tended to throw a certain amount of discredit upon all that class of evidence, and to demand that it be subjected to the closest scrutiny. Indeed, the frequency with which testimony is tortured, or fabricated outright, to build up the defence of a prior use of the thing patented, goes far to justify the popular impression that the inventor may be treated as the lawful prey of the infringer. The doctrine was laid down by this court in Coffin v. Ogden, 18 Wall. 120, 124, that "the burden of proof rests upon him," the defendant, "and every reasonable doubt should be resolved against him. If the thing were embryotic or inchoate; if it rested in speculation or experiment; if the process pursued for its development had failed to reach the point of consummation, it cannot avail to defeat a patent founded upon a discovery or invention which was completed, while in the other case there was only progress, however near that progress may have approximated to the end in view.” This case was subsequently cited with approval in Cantrell v. Wallick, 117 U. S. 689, 696, and its principle has been repeatedly acted upon in the different circuits. Hitchcock v. Tremaine, 9 Blatchford, 550; Parham v. American Button-Hole Machine Co., 4 Fisher, 468; American Bell Telephone Co. v. Peoples' Telephone Co., 22 Fed. Rep. 309.

The testimony of the defendant tended to show the existence, public exhibition and use of a number of fences prior to the date of the application in this case; but what is known as the Morley fence is supported by the largest amount of evidence, and was the one the learned District Judge who heard this case in the court below held to have been an anticipation of this patent. (33 Fed. Rep. 261.)

A panel of this fence appears to have been exhibited at a county fair in Delaware County, Iowa, at Delhi, in 1858 and 1859. It appears that Morley owned lands in Delaware County; that his family lived in Pennsylvania; that for a number of years, from 1858 to 1864, he spent a portion of his