
145 U.S. 302 (1892)
HOYT
v.
HORNE.
No. 336.
Supreme Court of United States.
Argued April 26, 27, 1892.
Decided May 16, 1892.
APPEAL FROM THE CIRCUIT COURT OF THE UNITED STATES FOR THE DISTRICT OF MASSACHUSETTS.
*306 Mr. Philip Mauro and Mr. Anthony Pollok for appellant.
Mr. Frederick P. Fish (with whom was Mr. W.K. Richardson on the brief) for appellee.
MR. JUSTICE BROWN delivered the opinion of the court.
The engine in ordinary use by paper makers for the reduction of rags to pulp prior to the invention in question consisted of a tub about fourteen feet in length with straight sides and semicircular ends. Through the centre of this ran a vertical partition called the mid-feather, extending lengthwise of the tub, and with sufficient room between the ends of *307 the partition and the ends of the tub to allow the pulp to pass around from one side of the tub to the other. Midway of the tub and between the mid-feather and one side was a wheel or beater-roll, armed with knives, placed longitudinally upon the periphery of the wheel. Beneath the roll were corresponding knives in the bed-plate, and by the revolution of the wheel the rags were drawn between these knives and reduced to pulp. At one side of the roll the bottom of the tub was curved upwards forming a ridge or dam, termed a back-fall, about four inches high extending across the channel parallel with the roll. The beater-roll revolved away from the top of the back-fall, and the material being lifted by the rotation of the roll to the top of the back-fall, slid down the incline by gravity, which was the only force acting to cause a flow of nearly thirty feet, from the back of the beater-roll around to the front of it again. The speed of the pulp was thus necessarily very slow.
1. The novelty and patentability of the Hoyt patent were not denied, though two prior patents were referred to for the purpose of limiting its claims. The Umpherston engine was patented in England in April, 1884, a few months before the Hoyt patent was issued in this country. This machine differs from the old tub only in the fact that the mid-feather runs horizontally instead of vertically, and the return passage or channel for the pulp is underneath instead of alongside of the channel containing the beater-roll. Apparently the only advantage which it possesses over the old one is in economy of floor space.
The Cooke engine, patented in England in 1880, is a machine of the type known as disk-grinders, and is not a beating engine of the type of the machines involved in this suit. It has no beater-roll, the grinding being done by two disks at the end of the tub between which the pulp is drawn in at the centre of the disks, and works its way outward to the periphery between the grinding surfaces. It seems to us to have little bearing upon the present case except in the fact that the grinding mechanism is located at the end of the tub instead of in the centre.
The Hoyt engine differs from the old tub in ordinary use *308 in two or three important particulars. First, the beater-roll is located at the end of the tub, instead of in the centre, having in this particular a certain resemblance to the Cooke machine; second, the mid-feather runs horizontally instead of vertically, a feature in which it resembles the Umpherston engine; and, third, the beater-roll extends across the whole width of the tub, and its revolutions are toward instead of away from the top of the back-fall or dam. The result of this is such a greatly increased speed in the flow of the pulp that it is said to be brought in contact with the knives twelve times as often as was possible in the old tub or engine.
The circulation of the material around the roll in vertical planes is the salient feature of the Hoyt invention, and its utility is shown in its general adoption by paper makers.
2. The main question in the case is that of infringement. In the defendant's engine the beater-roll is also located at the end of the tub and extends across its entire width; the top of the back-fall or dam also extends across the entire width in front of the beater-roll, but narrows at one side as it descends to the bottom of the tub to one-half of its width. The mid-feather is made vertical instead of horizontal, so that the pulp after it leaves the dam circulates in a horizontal instead of a vertical plane; but as it returns to the beater-roll it passes back under the dam, spreading out to the entire width of the tub, and is taken up by the beater-roll precisely as in the Hoyt patent. It is insisted by the defendant in this connection that there is no infringement of the first claim of the Hoyt patent, since the pulp is not circulated "in vertical planes," nor is it delivered by the beater-roll "into the upper section of the vat," as specified in that claim. Literally it is not. A technical reading of the specification undoubtedly required that the mid-feather should run horizontally instead of vertically; but the object of this was that the pulp should be received and delivered by the beater-roll along its entire length, viz.: across the entire width of the tub, and this is accomplished in the same way in both devices. In both engines the beater-roll revolves toward the top of the dam or back-fall, and a similar acceleration of speed is obtained. How *309 the pulp shall circulate at the other end of the tub is a matter of small consequence so long as it shall circulate in vertical planes at the point where it comes in contact with the roll.
An additional function is claimed for the Horne device in the fact that the pulp, falling as it descends the dam from a vertical to a horizontal plane in a kind of torsional current, is more thoroughly mixed than in the Hoyt device, where the pulp continues to flow in parallel lines from the time it is delivered by the beater-roll to the time it is received by it again. This may be true, and defendant's engine may be in this particular an improvement upon the other; but he has none the less succeeded in appropriating all that was of value in the Hoyt device, viz.: the beater-roll at the end of the tub, extending across its entire width, and the circulation of the pulp in vertical planes at the only point where such circulation is of value. The substitution of a vertical for a horizontal mid-feather at the inoperative end of the tub is merely the use of an old and well known mechanical equivalent, and obviously intended to evade the wording of the claims of the Hoyt patent. Winans v. Denmead, 15 How. 330. Indeed, the ingenuity displayed in this evasion is only equalled by the ingenuity with which it is concealed in the specification of the defendant's patent, and the function of a more thorough mixture of the pulp put forward as the salient feature of the invention. The actual intent to evade is the more manifest from the fact that Horne, under a contract with the plaintiff, made seventeen machines according to the plaintiff's patent, but owing to some disagreement as to the quality of the work done by him, the contract was terminated, and Horne began the production of his own engines, and subsequently took out a patent for his invention.
We are, therefore, of opinion that defendant's machine is an infringement of the first claim of the plaintiff's patent. Whether it be an infringement of the second claim admits of more doubt, since that contemplates a horizontal partition dividing the body of the vat into an upper and lower section or passage. We do not, however, find it necessary to pass upon this question.
*310 The decree of the court below is, therefore,
Reversed, and the case remanded with instructions to enter a decree for the plaintiff upon the first claim, and for further proceedings in conformity with this opinion.
