law. it nevertheless involves an estimate on the part of the court of the force and efficacy of the evidence.

It is our opinion, therefore, that the supreme court of the District at general term erred in dismissing the appeal from the order at special term denying the motion for a new trial on the ground that the verdict was against the weight of evidence. It should have entertained and considered the appeal on that ground.

It is urged in argument, however, that the error did not prejudice the plaintiff in error, because the court necessarily passed upon the same matter in considering and sustaining the ruling of the court at special term in refusing to instruct the jury to return a verdict in favor of the defendant upon the evidence offered by the plaintiff; but the question arising on this ruling, and that on the motion for a new trial at the conclusion of the whole evidence, were not identical. It might well be that on the plaintiff's evidence there was a case sufficiently made out to submit to the jury, while on the whole testimony it might fairly be a question whether the verdict was not against the weight of the evidence, in that sense which would justify the court in granting a new trial. Of course, nothing we have said in this opinion is to be construed as indicating any rule of decision in such cases, or is intended in the least to narrow the province of the jury as the proper tribunal for determining questions of fact in trials at common law. The relation of the court to the jury, together constituting the appointed tribunal for the administration of the law in such cases, is regulated by fixed and settled maxims. The legal discretion of the supreme court of the District, whether sitting at general or special term, in granting or denying motions to set aside verdicts and grant new trials, is not by law submitted to the review of this court. The only point in judgment here is that the plaintiff in error was entitled by law to have that discretion exercised by the supreme court at general term, and that that court committed an error of law in refusing to consider his appeal from the order at special term denying his motion for a new trial, based on the ground that the verdict was against the weight of the evidence.

For this error the judgment of the supreme court of the District of Columbia at general term is reversed, and the cause remanded, with directions to take further proceedings therein in conformity with this opinion.

(121 U. S. 617)

SNOW v. LAKE SHORE & M. S. Rr. Co.1

(May 2, 1887.)

PATENTS FOR INVENTIONS-IMPROVEMENT IN STEAM BELL-RINGERS-CONSTRUCTION OF CLAIMS.

Letters patent No. 127,933 were granted June 11, 1872, to the assignee of George B. Snow for an improvement in steam bell-ringers; the object of the invention being the prevention of leakage, either of water or steam, without resorting to the use of stuffing-boxes, as was required under the prior state of the art. The specifications described as part of the combination a piston disconnected from its rod to prevent any lateral strain being communicated to it, thereby decreasing to some extent the wear of the piston in the cylinder. The defendants used bell-ringers constructed in conformity with letters patent No. 154,394, granted August 25, 1874 to Charles H. Hudson, the most valuable parts of which were suggested by the Snow patent, but did not contain the piston disconnected as above mentioned. Held, affirming the decree of the circuit court, (18 Fed. Rep. 602,) that the said ar rangement of the piston being made a material part of the invention, the Snow pat ent must be limited to a combination containing the same, and the defendants therefore, did not infringe.

Appeal from the Circuit Court of the United States for the Northern District of New York.

James A. Allen, for appellants. Geo. Payson, for appellees.

'Afirming 18 Fed. Rep. 602.

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MATTHEWS, J. The appellants, who were complainants below, filed their bill in equity, August 7, 1882, against the defendant, to restrain the alleged infringement of letters patent No. 127,933, granted to the Buffalo Dental Manufacturing Company, as assignee of George B. Snow, on June 11, 1872, for a new and useful improvement in steam bell-ringers; the Buffalo Dental Manufacturing Company being a joint-stock association under the laws of the state of New York, of which the appellants were the sole officers, directors, shareholders, associates, and persons in interest. The specifications, with drawings annexed, of this patent are as follows:

"Specification describing certain improvements in steam bell-ringing apparatus; invented by George B. Snow, of Buffalo, in the county of Erie, state of New York.

"This invention relates to the construction of a steam bell-ringer in such a manner as to prevent any apparent leakage, either of water or steam, without resorting to the use of stuffing-boxes, and also to cause the admission and release of the steam directly by the motion of the piston, and without the use of any intermediate parts between the piston and valves.

"Referring to the annexed drawing, Figure 1 is an elevation of the device as applied to the bell of a locomotive. Fig. 2 is a vertical section of the steam-cylinder on the plane, a, b, on an enlarged scale. A is a single-acting steam-cylinder, connected to the crank, B, on the bell-yoke by the slotted rod, C. This rod should be of such a length that the piston, G, will be forced to the bottom of the cylinder, as the crank, B, passes its lower center; the slot through which the crank-pin passes being long enough to allow the crank to pass its upper center freely, notwithstanding the disproportion between the throw of the crank, B, and the length of stroke of the piston-rod, D. The piston, G, is disconnected from its rod, D, to prevent any lateral strain being communicated to it, thereby decreasing to some extent the wear of the piston in the cylinder. The piston should be considerably longer than its length of stroke. The piston-rod, D, passes through a sleeve in the cylinder cover, I, which should be long enough to steady it and act as a guide, and is limited in its upward motion by the collar, d. E is a conical exhaustvalve, seating upward against the bottom of the piston, G. F is the steamvalve, also conical, and seating upward, containing within itself the tail of the exhaust-valve, E; such an amount of motion being permitted between the two that the steam-valve, F. will be raised to its seat, and the exhaust-valve, E, be opened as the piston approaches the upper end of its stroke. Exhaust passages, M, m, are formed in the piston, G, which communicate with the holes, m', in the side of the cylinder by means of annular grooves turned in the side of the piston; the openings, m', being of such a number and so disposed as to insure a constant communication with the passage, M. The thimble, H, forms an annular space around the cylinder, from which the steam escapes through the passage, O. If the piston is closely fitted, it will wear a long time with very little leakage, and what there may be will be caught in the annular grooves in the side of the piston, and passed at once through the exhaust passages, m'; thus preventing any leakage around the piston-rod, D. It is advisable to use a packing of a single ring at the lower part of the piston, not so much to avoid leakage as to sustain the piston at the upper end of its stroke by the elasticity of the ring until it is brought to the bottom of the cylinder by the return swing of the bell.

"The bell being set in motion, the crank, B, drives the piston to the bottom of the cylinder, closing the exhaust-valve, and forcing open the steam-valve, admitting steam to the cylinder from the space, S. As the piston is driven upward, the exhaust-valve is carried with it; and, as the piston approaches the end of its stroke, the steam-valve is also raised to its seat, after which the exhaust-valve is opened. As the pressure is relieved, the exhaust-valve drops, leaving the passage, M, entirely clear during the return stroke, which is made

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by the momentum of the bell on its return. The arrangement of valves shown is not essential, as the exhaust-valve may be placed in a cavity in the body of he cylinder opening into the exhaust-passage, and both the steam and exhaustvalves be closed by the direct impulse of the steam; the openings, m', being made low enough in the cylinder to allow the piston to pass them at the upper end of the stroke; or, by using a piston in the form of an inverted cup, the steam and exhaust may be worked through openings in the side of the piston and cylinder, the expansion of the steam doing the work. The disadvantage of the first of these plans is that the valves are closed so violently that they soon wear out; of the second, the difficulty of getting rid of water of condensation.

"Having thus fully described my device, I claim as my invention (1) the combination of the cylinder, A, piston, G, piston-rod, D, slotted rod, C, and crank, B, when constructed and operated substantially as described; (2) the combination of the valves, E and F, both seating upward, with the piston, G, and passages, M, m, m', for the purpose of admitting steam to and exhausting it from under the piston, G, substantially as described."

The infringement alleged is of the first claim only, and consists in the use by the defendant below of steam bell-ringers constructed and operated in conformity to the drawings and specifications of letters patent granted August 25, 1874, No. 154,394, to Charles H. Hudson for a new and useful improvement in steam bell-ringing apparatus. The specifications and illustrative drawings of that patent are as follows:

"To All Whom It may Concern: Be it known that I, Charles H. Hudson, of the city and county of Dubuque, Iowa, have invented a new and useful improvement in steam bell-ringing apparatus, of which the following is a specification: This invention relates to steam-engines designed for ringing bells on locomotives, and in other places, and consists in the construction and arrangement of parts, as hereinafter described, and specifically indicated in the claim.

"In the accompanying drawings, Figure 1 represents a vertical section of Fig. 2 on the line, x, x; and Fig. 2 is a horizontal section taken on the line, y, y, Fig. 1. Similar letters of reference indicate corresponding parts. This bellringing engine may be worked with either steam or air. A is the cylinder; B, the piston. C is the piston-rod. D is the valve-ring. E is a rod which is hinged to the piston-rod at the point F. This rod, E, slides in the tube, G, which is attached to the bell-crank. This connection is such that the lower end of the tube, G, will be at the shoulder, H, when the bell-crank is at the lowest point, and the piston at the bottom of the stroke. The movement of the tube upon the rod, E, will allow the bell to be turned over and the bellcrank to go to its highest point freely, while the piston is at the lowest point. I is the exhaust-port; J, the inlet-port. The valve-ring, D, is so arranged, in regard to the ports, that the movement of the piston to the lowest point moves the valve-ring down, and closes the exhaust and opens the inlet-port. When the piston moves to the other end of the stroke, the ring is moved in the other direction, and the inlet is closed and the exhaust is opened. K is the inlet passage. Lis the exhaust passage. m is a small opening into the exhaust passage to allow any steam which may pass the piston to escape. O, O, are ports or passages in the lower head of the double piston, to permit the steam (or air, if used) to act against the lower head of the cylinder.

"When the bell is in motion, the bell-crank will press the tube down on the rod, and force the piston to the bottom of the stroke, and thereby close the exhaust and open the inlet ports. When the crank has passed the center of the stroke, the steam admitted by the movement of the valve-ring presses the piston up, and throws up the bell. The tube connection allows the bell-crank to move freely upward after the piston has reached the end of its stroke, cut off the steam, and open the exhaust-port. The return swing of the ball is

followed by the same action of the parts. N is a small set-screw in the tube G, the end of which enters a groove, or acts against a flat side of the rod. E, to prevent the piston-rod from turning. Any other suitable device may be adopted for the purpose. I do not claim, broadly, the combination of a valvering with a piston and cylinder for cutting off admission and escape of steam

alternately; but, having thus described my invention, I claim as new, and desire to secure by letters patent, in combination with the vertical cylinder, A, having inlet and exhaust ports, K, J, and I, L, m, the double piston, B, having openings or passages, 0, 0, in its lower head, and the valve-ring, D, arranged below the upper head thereof, as shown and described, to operate as specified."