ber has been subjected to vulcanization, thus making the packing a homogeneous whole and not a strip rolled up upon itself and thus kept together. Therefore, none of the patents introduced by the defendants show the Gately invention. It is true that McBurney shows a part of the combination or article patented by Gately, and McLean shows a rubber backing; but the invention of Gately was new and patentable. As to the other evidence and exhibits put in by the defendants, none of them show a rubber backing of pure gum and a front wearing portion united by vulcanization to the back portion, so as to produce a homogeneous article; but they all show something which Gately dispensed with that is, an elastic core and a wrapping of fibrous or textile material around such core. Where the packing has a covering of textile material wrapped around the elastic portion of the packing, the wearing surface presented to the piston-rod cannot continuously, as in the Gately packing, be identically the same surface in character, nor can such feature exist, unless Gately's or McBurney's wearing portion and the elastic backing are united as a homogeneous whole by the process of vulcanization.

Within the requirements of Atlantic Works v. Brady (C. D., 1883, 214; 107 U. S., 192, 200) we think that Gately made a substantial discovery or invention, which added to our knowledge and made a step in advance in the useful arts; that, within the case of Hollister v. Benedict Mfg. Co., (113 U. S., 59, 73,) what Gately did was not merely the work of a skilled mechanic, who applied only his common knowledge and experience, and perceived the reason of the failure of McBurney's packing, and supplied what was obviously wanting, and that the present case involves not simply

the display of the expected skill of the calling,

involving

only the exercise of the ordinary faculties of reasoning upon the materials supplied by a special knowledge, and the facility of manipulation which results from its habitual and intelligent practice,

but shows the creative work of the inventive faculty.

The defendants made two forms of packing, one of them identically the packing of the Gately patent; in the other, a little over one-half of the packing was constructed identically in accordance with the Gately invention, and a little less than one-half was so constructed, except that the canvas was not cut on the bias. This feature made the packing relatively stiffer and injured it; and, even as it was made, like surfaces, or surfaces of the same character, were presented to the pistonrod throughout the entire wear of the packing in the box.

It is remarked by Judge Nixon in his opinion, as a fact not to be overlooked and having much weight, that the Gately packing went at once into such an extensive public use as almost to supersede all packings made under other methods; and that that fact was pregnant evi

dence of its novelty, value, and usefulness. (Smith v. Goodyear Dental Vulcanite Co., C. D., 1877, 171; 93 U. S., 486, 495, 496; Webster Loom Co. v. Higgins, C. D., 1882, 285; 105 U. S., 580, 591.) It may also be added, that the evidence shows that the Gately packing was put upon the market at a price from fifteen to twenty per cent. higher than the old packings, although it cost ten per cent. less to produce it. The decree of the circuit court is affirmed.

[Supreme Court of the United States.]

CROSBY STEAM GAGE AND VALVE COMPANY v. CONSOLIDATED SAFETY VALVE COMPANY.

Where defendants have infringed plaintiffs' patent by the manufacture and sale of valves the entire commercial value of which lies in a feature covered by plaintiffs' patent, they are liable in damages for all profits realized by them from such manufacture and sale.

2. SAME-SUBJECT OF INQUIRY.

The only subject of inquiry in estimating the amount of damages is the profit made by defendant on the articles which it sold at a profit and for which it received payment; and losses incurred by the defendant through its wrongful invasion of the patent are not chargeable to the plaintiff, nor can their amount be deducted from the compensation which the plaintiff is entitle to receive.

3. SAME-INTEREST on DAMAGES AWARDED.

Delay caused by the court, or not attributable to the plaintiff in coming to a conclusion on a masters' report where the amount of damages found by that report is confirmed, ought not to deprive the plaintiff of interest on the amount found by the master. Under such circumstances the account ought to be considered as liquidated on the day when the master's report is filed.

APPEAL from the Circuit Court of the United States for the District of Massachusetts.

Mr. I. H. Millett for the appellant.

Mr. Edmund Wetmore and Mr. Thomas William Clarke, for the appellee.

Mr. Justice BLATCHFORD delivered the opinion of the Court.

On the 27th of May, 1879, the Consolidated Safety Valve Company, a Connecticut corporation, brought a suit in equity in the Circuit Court of the United States for the District of Massachusetts, against the Crosby Steam Gage and Valve Company, a Massachusetts corporation, for the infringement of Letters Patent No. 58,294, granted to George

W. Richardson, September 25, 1866, for an improvement in steam safety-valves. The claim of that patent was as follows:

What I claim as my improvement, and desire to secure by Letters Patent, is—

A safety-valve with the circular or annular flange or lip c c, constructed in the manner, or substantially in the manner, shown, so as to operate as and for the purpose herein described.

On the 2d of June, 1879, the same plaintiff brought a suit in equity in the same court against the same defendant, for the infringement o Letters Patent No. 85,963, granted to the same George W. Richardson, January 19, 1869, for an improvement in safety-valves for steam boilers or generators. The claim of that patent was as follows:

What I claim as new, and desire to secure by Letters Patent, is

The combination of the surface beyond the seat of the safety-valve, with the means herein described for regulating or adjusting the area of the passage for the escape of steam, substantially as and for the purpose described.

In the answers in the two suits, the defense of want of novelty was set up, and alleged anticipating patents were referred to; infringement was denied; and it was averred that the valves made and sold by the defendant were the inventions of George H. Crosby, and were described in two patents granted to him and owned by the defendant, one, No. 159,157, dated January 26, 1875, and the other, No. 160,167, dated February 23, 1875.

The same proofs were taken in the two suits, and they were heard together in the circuit court; in each suit a decree was made dismissing the bill, (7 Fed. Rep., 768;) and from each decree the plaintiff appealed to this Court. Non-infringement was found by the circuit court. This Court (C. D., 1885, 180, 113 U. S., 157) reversed the decree in each case and directed the circuit court to enter a decree in each case sustaining the validity of the patent, decreeing infringement, and awarding an account of profits and damages.

On receiving the mandate of this Court in the suit on the patent of 1866, the circuit court, on the 18th of May, 1885, entered a decree in conformity therewith and for a recovery by the plaintiff of profits and damages from February 15, 1879, and ordered a reference to a master to take an account of such profits and damages. A like decree was made on the mandate in the suit on the patent of 1869. The date of February 15, 1879, was taken because that was the time when the title to each of the patents became vested in the plaintiff.

The master took voluminous proofs, and filed his report on the 5th of August, 1889, covering both of the suits. The report of the master found that the total profits which the defendant had derived from its manufacture and sale of steam safety-valves containing the improvement described and claimed in the patent of 1866, from February 15, 1879, to September 25, 1883, the date of the expiration of the patent, amounted to $40,344.59. Both parties filed exceptions to the report; and on the 11th of October, 1890, the circuit court entered a decree

overruling both sets of exceptions and awarding to the plaintiff a recovery for the $40,344.59, with interest thereon from August 5, 1889, the date of the filing of the master's report, and the costs of the suit. From this decree the defendant has appealed. The opinion of the circuit court is reported in ante, 300; 44 Federal Reporter, 66.

The master says, in his report in the case, in respect to the patent of 1866, which he calls No. 1,184, that, for the period from February 15, 1879, to September 25, 1883, he attributes the entire commercial value of the valves manufactured and sold by the defendant to the improvement covered by the patent of 1866. He adds:

Richardson's invention, as described and claimed in that patent, revolutionized the art of relieving steam-boilers from steam-pressure rapidly approaching the dangerous point. It made effective for that purpose-rapidly and with comparatively small loss of steam-apparatus described in other patents, which very nearly embodied Richardson's invention, but did not actually contain it. The Supreme Court in these cases has defined this invention, and has declared it to be a vital one—a life-giving principle to structures very nearly approaching, but not quite containing an embodiment of Richardson's discovery.

The master also says in his report:

It was contended before me that none of the complainant's valves of commerce contained this invention of Richardson, but, upon the whole evidence, with specimens of all the different valves put on the market by the complainants before me, I find that they all contained Richardson's improvement of 1866. The Supreme Court has decided in these cases that the defendant's valves contain this invention, and it is under this decision that the accounting in No. 1,184 is before me. Eliminate this invention from the defendant's valves and they would be commercially worthless. No substitute for this invention has been suggested to me, and I know of none which the defendants could have used in its place to have made their valves of commercial value. The defendants claim that some of the profits which they have made are due to the peculiar form of their valves; but the form which they used in making their valves was the form in which they clothed the Richardson invention, the life of their valves, and without that life the Crosby form is worthless.

The specifications and drawings of the two patents of Richardson are set forth at length in the report of the cases in C. D., 1885, 180; 113 U.S., 157. The opinion of this Court said (pages 194; 178:)

There is one structural difference between the two valves, which is now to be mentioned. In the Richardson valve all the steam which escapes into the open air escapes from the huddling-chamber, through a stricture which is smaller than the aperture at the ground-joint. In the defendant's valve, the valve proper has two ground-joints, one at the inner periphery of the annulus and the other at its outer periphery, and only a part of the steam, namely, that which passes through one of the ground-joints, passes into the huddling-chamber and then through the stricture, the other part of the steam passing directly from the boiler into the air through the other ground-joint. But all of that part of the steam which passes into the huddling-chamber and under the extended surface, passes through the constriction at the extremity of such chamber, in both valves, the difference being one only of degree, but with the same mode of operation.

In respect to this point, one of the briefs for the appellant, now submitted, says:

The appellants' valve, in this case known as the Crosby valve and made in accordance with the Crosby patents, is so constructed that it has two ground-joints.

When the valve rises by reason of increased pressure, part of the steam escapes through one ground-joint directly into the open air and part of the steam escapes through the other ground-joint into a huddling-chamber, and thence into the air through orifices which form an aperture less than the ground-joint orifice through which it enters said huddling-chamber. Although the relief to the boiler caused by the blowing off of the valve was, in consequence of this double mode of escape for the steam, due to the combined effect of its escape through the huddlingchamber and its escape through the second ground-joint, yet, as all that part of the steam which entered the huddling-chamber passed through the strictured opening, the court held that the valve contained the Richardson device, and was, therefore, an infringement.

The master further says, in his report:

The defendants claimed before me that the complainants, in the accounting in 1,184, which relates only to the Richardson patent of 1866, should prove specifically the value of the invention secured to them under that patent as used by the defendants, and that, as it was claimed by complainants (and the Supreme Court has so decided) that defendants used also Richardson's invention of 1869, the value of the invention secured to the complainants by the 1869 patent must be determined, and not made an element in the recovery to be had under the accounting in 1,184. I have no means of determining the value of that invention as used by the defendants from February 15, 1879, to September 25, 1883, or of stating in dollars and cents how much of the profits of the defendants during that period is due to that invention. The complainants claimed that during that period all the profits of the defendants were due to the Richardson invention of 1866, and, as the Richardson invention of 1869 belonged also to the complainants and as the complainants and defendants were respectively the same in each case, 1,184 relating to the said invention of 1866 and 1,199 relating to the invention of 1869, and as the said period from February 15, 1879, to September 25, 1883, was included within the period to be covered by the accounting in each case, no injustice is done the defendants in acceding to the complainants' claim in this regard; and this is especially so in view of the fact that the defendants claimed that the adjustable device as shown in the Richardson patent of 1869 is worthless as such, and that the cost of the Crosby valve is less without the said so-called adjustable ring and is a better and more useful safet appliance.

The master also found that the plaintiff had suffered no damages in addition to the profits to be assessed against the defendant, in regard to the patent of 1866.

The defendant's exceptions to the master's report cover the following points: (1) The disallowance to the defendant of the sum of $1,978.34; (2) the finding that the Richardson valve sold by the plaintiff contained the invention set forth in the patent of 1866; (3) the finding that the entire commercial value of the valves made and sold by the defendant, between February 15, 1879, and September 25, 1883, was due to the improvement covered by the patent of 1866; (4) the failure to find that the plaintiff was entitled to recover only for the ascertained value of the improvements covered by the two patents over and above the value of previous safety-valves known to the art and open to be used by the defendant; (5) the failure to require the plaintiff to show what in fact was the value attributable to the improvement of 1866; (6) the failure to require the plaintiff to show what was the value of the improvement of 1866, in comparison with the value of safety-valves previously known