parts are at the sides of the head end of the skin, as the skin is split open at the under side. At these parts of the skin the hairs point outwardly and backwardly and are the most troublesome to cut or pluck, as they lie down close to the skin when it is drawn over the stretcher-bar. A sharp and quick rub over these parts of the skin from the edge toward the center of the skin is therefore necessary, so as to straighten up the hairs and present them to the action of the cuttingknives. When the skin is in place, the stationary card E is drawn backward a few times over that part of the skin that is upon the stretcher-bar B, so as to card back the fur and hair and produce thereby a parting of the fur at that part of the skin then covering the edge of the stretcher-bar. Onehalf of the fur upon that section of the skin will by the parting be kept above and the other half below the edge of the stretcherbar. This permits the hair upon that section of the skin in front of the edge of the stretcher-bar to rise through the fur and keep its place with less trouble than when more fur is acted upon. When the fur and hair have been carded back by the card E, the same is fastened to the stretcher-bar by thumbscrews. The card is set back from the edge of the stretcherbar to a distance a little more than one-half of the length of the fur for the purpose of holding the fur and preventing it from moving forward until the forward motion of the skin takes place. The card at the back of the rotary knife passes then over the skin in front of the edge of the stretcher-bar and draws out all the fur and hair on that section, so that the fur and hairs so drawn out assume their natural positions-that is, the positions which they would have if the skin were drawn over the edge of the stretcher-bar without anything for holding back the fur and hair. As soon as the card at the back of the rotary knife has passed over the section of the skin in front of the stretcher-bar the rubbers are quickly moved over the same toward the center, whereby the hairs that lie down sidewise are raised and pointed outwardly, causing them to stand upright. The rotary separating-brush is then quickly

moved upward and forward and revolved in front of the skin at the edge of the stretcher-bar, so as to separate the fur from the hairs, brushing down the former, and leaving the stiff hair standing out. The rotary separating-brush is then quickly moved backward and downward, so as to carry with it the separated fur, which is then held in position by the oscillating guard that follows the brush and carries the fur still farther back and holds it in position, while the vertical knife is raised and shears off, in conjunction with the rotary knife, the forward-projecting hairs, as shown in Fig. 1. The separatingbrush, after it has accomplished its work, is lowered sufficiently so as not to touch the skin at all, except when it is in front of the working-edge of the stretcher-bar. The next section of the skin is now moved by the feed-rollers over the edge of the stretcher-bar, and the same operation of the parts produced by the next rotation of the driving-shaft, and so on until the skin is finished.”

The great merit of this invention is said to consist in the use of the brush, applied by means of the mechanism shown, so as to brush down the fur, and permit the long hairs, which should be removed, and which rise at the edge of the stretcherbar, when the pelt is drawn over it to be acted upon by the knives, when the fur is brushed away, so as not to be injured.

In determining the construction to be given to the claim in suit, which is alleged to be infringed, it is necessary to have in mind the nature of this patent, its character as a pioneer invention or otherwise, and the state of the art at the time "when the invention was made. It is well settled that a greater degree of liberality and a wider range of equivalents are permitted where the patent is of a pioneer character than when the invention is simply an improvement, may be the last and successful step, in the art theretofore partially developed by other inventors in the same field. Upon this subject it was said by this court, Westinghouse v. Boyden Power Brake Co., 170 U. S. 537, quoted with approval in Singer Co. v. Cramer, 192 U. S. 265:

"To what liberality of construction these claims are entitled depends to a certain extent upon the character of the invention, and whether it is what is termed in ordinary parlance a 'pioneer.' This word, although used somewhat loosely, is commonly understood to denote a patent covering a function never before performed, a wholly novel device, or one of such novelty and importance as to mark a distinct step in the progress of the art, as distinguished from a mere improvement or perfection of what had gone before. Most conspicuous examples of such patents are: The one to Howe of the sewing machine; to Morse of the electric telegraph; and to Bell of the telephone. The record in this case would indicate that the same honorable appellation might safely be bestowed upon the original airbrake of Westinghouse, and perhaps also upon his automatic brake. In view of the fact that the invention in this case was never put into successful operation, and was to a limited. extent anticipated by the Boyden patent of 1883, it is perhaps an unwarrantable extension of the term to speak of it as a 'pioneer,' although the principle involved subsequently and through improvements upon this invention became one of great value to the public."

While it may be admitted that the Sutton patent was a distinct step in the art, and is entitled to protection as a valuable invention, nevertheless it cannot be said to be a pioneer patent in any just sense. In the English Lake patent of 1881, of which more will be said hereafter, there is doubtless a suggestion of the use of brushes for the purpose of separating the fur from the long hair to be removed. And so in the Covert patent of 1884, which was the subject of consideration by Judge Wheeler in the case of Cimiotti Unhairing Co. v. Mischke, 98 Fed. Rep. 297. In that case it was said that Covert's patent had been mechanically but not commercially successful, and that in lieu of a rotating separating brush, shown in Sutton's patent, Covert used a revolving cloth-covered cylinder, and it was held that this was not equivalent to the separating brush, and Sutton's invention was an advance upon anything

theretofore shown.. Of the Covert patent Judge Cox, in the course of an able opinion sustaining the Sutton patent, Cimiotti Unhairing Co. v. American Machine Co., 115 Fed. Rep. 498, 502, said:

"Covert came nearer than any one else to a successful machine. He had but one more step to take and here he became bewildered and went astray. He missed the apparently simple arrangement of the rotary brush which alone was necessary. It will not do to say that the prior art showed such a brush. Every element of the combination in controversy was unquestionably old, but there was nothing in the prior art to suggest a rotary brush working in the environment shown in the Sutton patent. There was nowhere a rotary brush making a 'part' on a keen-edged stretcher-bar and brushing the fur down and out of the reach of the cutting-knives during the moment necessary for the removal of the stiff hairs. It is the presence of this element in the combination which produces a new result and entitles its originator to protection." In the same case, Judge Wallace (p. 505), in his concurring opinion, says:

"I do not think the machine of the Sutton patent a prodigious advance upon that of the prior Covert patent, and I think a higher degree of merit has been attributed to it than it deserves; but it was enough of an advance to be patentable and to deserve protection against an infringing machine which appropriates it."

Furthermore, it appears that while the Cimiottis acquired an exclusive license under the Sutton patent in 1888, the same was not put into commercial use until the introduction of coney skins as a substitute for sealskins, about the year 1890. During this time the Cimiottis were unhairing a large number of skins and preferred to continue to use the air-blast machine of their own invention while paying tribute to Sutton. It was the introduction of the coney industry in 1890 that gave stimulus to the use of such mechanisms as those used by the Cimiottis and the respondent in this case. We think it fair

to say that this record discloses an invention of merit entitled to some range of equivalents in determining the question of infringement, but it is not one of those broad, initiative inventions where original thought has been embodied in a practical mechanism, which the courts have been ever zealous to protect, and to which a wide range of equivalents has been accorded.

Due weight is given to the Sutton patent when it is given credit for dispensing with the plate which Covert had in addition to the brush, and which he supposed would carry down the fur away from the cutting mechanism, but which Sutton has accomplished in giving, in a measure at least, this added function to the brush of not only parting the fur, but carrying it down and away in preparation for the clipping by the knives. Any one who accomplishes the same purpose by substantially the same mechanism, using the elements claimed in Sutton's patent, may be held to be an infringer.

Sutton has taken the step which marks the difference between a successfully operating machine and one which stops short of that point, and that advance entitles him to the protection of a patent.

The argument here is confined, as to the alleged infringement, to the eighth claim of the Sutton patent, which is as follows:

"8. The combination of a fixed stretcher-bar, means for intermittingly feeding the skin over the same, a stationary card above the stretcher-bar, a rotary separating-brush below the same, and mechanism, substantially as described, whereby the rotary brush is moved upward and forward into a position. in front of the stretcher-bar, substantially as set forth."

The elements of this claim are five in number: 1, a fixed stretcher-bar; 2, means for intermittently feeding the skin over the same; 3, a stationary card above the stretcher-bar; 4, a rotary separating brush below the same; 5, mechanism whereby the rotary brush is moved upward and forward into a position in front of the stretcher-bar, "substantially as set forth."