Opinion of the Court.

"Their books show that they thus treated 23,322,777 lbs. of fat during the period in question, saving 2,798,733 lbs. of lime and 6,880,219 lbs. of sulphuric acid, upon the basis above mentioned. The testimony shows the average cost of lime to have been $.3526 per hundred pounds, and the average cost of the acid $2.527 per hundred."

It appears, by the testimony of the defendants themselves, that, when they manufactured by the old process, they used 14 pounds of lime to each hundred pounds of fat treated, and 3 pounds of sulphuric acid to each pound of lime. It is contended by the plaintiff that that process, as used by the defendants, should be the standard of comparison in this suit; and that, according to the preponderance of evidence, the amount of lime, at least, so used by them, was a necessity in that process. But the plaintiff has the burden of proving the amount of profits that the defendants have made by the use of his invention. Blake v. Robertson, 94 U. S. 728; Elizabeth v. Pavement Co., 97 U. S. 126, 139; Dobson v. Hartford Carpet Co., 114 U. S. 439, 444, 445. And the question to be determined is, as stated by Mr. Justice Strong in delivering judgment in Mowry v. Whitney, "what advantage did the defendant derive from using the complainant's invention, over what he had in using other processes then open to the public and adequate to enable him to obtain an equally beneficial result?" 14 Wall. 620, 651. In determining that question, the expense of using the new process is doubtless to be ascertained by the manner in which the defendants have in fact conducted their business, and not by the manner in which they might have conducted it. But as to the comparative expense of the old process, the cost at which they used that process, if they did once use it, although strong evidence against them, because they may be presumed to have used it as economically as they could, is not conclusive evidence that the old process could not have been used at a less cost. To hold otherwise would be to hold infringers of a patent for a new process, who had ever used the old process, to a different measure of accounting from those who had never used the old process at all. In the former opinion, the court assumed, as the result

Opinion of the Court.

of the evidence, that the saponifying process required twelve or fourteen per cent of lime. 102 U. S. 731. There being evidence that such was the amount of lime used by some manufacturers under the old process, as well as that the average use of sulphuric acid under that process was 24 pounds to each pound of lime, we cannot say that the conclusion of the master ought to be set aside or modified as to either of these items.

The master finds that no material economy in operation has been secured by the change of process; and the testimony introduced by the plaintiff is not clear and decisive enough to overthrow his conclusion in this respect.

That part of the master's report, which relates to the amount saved in glycerine water, is as follows:

"It appears from the evidence that the average density of glycerine water obtained in the old lime-saponification process was only ° Baumé, while that obtained from the digesters was from 3° to 31°. It also appears that the concentration of the latter to 15° cost $1.55 per barrel at the respondents' factory.

"Assuming the cost of concentration to be in like proportion for each degree, it is claimed that concentration from 1° to 31° would cost nearly $.94 per barrel, and the cost of such concentration is an item of gain and saving realized by the respondents, by reason of the greater density of the glycerine water obtained from the digesters, for which they should be charged in this accounting. But there is no testimony establishing that the cost of concentration is in proportion to its degree, nor is it reasonable to assume such to be the fact; indeed, it is apparent that the cost of concentrating a single degree would be much greater in proportion than a more extensive operation, while an additional degree of concentration in an extensive operation would affect the cost but little.

"It appears in evidence that glycerine water was sold in the market at so much per barrel for each degree of density, and that the respondents sold it at the market price as it came from the digesters. It, however, required considerable concentration to prepare it for use, and they boiled it down to 15° for

Opinion of the Court.

the purchasers, charging the cost thereof to them. Provided as they were with facilities for such work, the additional cost of concentration from a still lower degree could not be great. The only witness whose testimony is directly in point says it would not be material. Besides, if paid by the purchaser, it would not affect the profits of the respondents.

"But the evidence does show a larger yield of glycerine by the new process. While the old lime-saponification process was in use, glycerine had no market value; consequently no effort was made to secure it, and there is no direct testimony as to the best results that could be secured by careful treatment, but the testimony shows that the average density of the glycerine which ran to waste was °, and that it was about equal in volume to the fat.

"It is claimed that the same volume of glycerine water was drawn from the digesters, while its density was much greater. But the master finds from the evidence that the respondents used two charges of water, each half the bulk of the fat, the first charge drawn from the digesters being the glycerine water sold by them. There was consequently double the volume of glycerine water in the former process, which accounts, in part, for difference in density; but the comparison still shows considerable loss due to various causes, which is further increased by the additional concentration required, the average result of tests made in various degrees of concentration indicating that it requires about 44 barrels of 4° to make one of 3o.

"The accompanying table B shows the quantity and value of glycerine water obtained by the respondents from the digesters, and also the number of barrels, concentrated to 3°, that could be obtained from the fat treated by lime saponification, and the value thereof at market prices, the difference being the amount gained by reason of the greater yield of glycerine from the digesters, viz., $61,701.77.”

As, according to the master's report and the whole evidence, the glycerine obtained by either process must, in order to be sold, be concentrated to 15°, and it is not shown how much, if anything, more it would cost to concentrate from ° to 15° than from 31° to 15°, and the purchaser in either case pays the cost

Opinion of the Court.

99

of concentration to 15°, the plaintiff fails to show that anything should have been allowed for the cost of concentration. But the finding of the master, that in the new process "the respondents used two charges of water, each half the bulk of the fat, the first charge drawn from the digesters being the glycerine water sold by them," and "there was consequently double the volume of glycerine water in the former process; as well as the corresponding statement in his table B, that the amount of glycerine water obtained by the new process was 65,312 barrels, while the amount that would have been obtained under the old process would have been 130,624 (misprinted in the record 134,624) barrels; is quite inconsistent with the sworn answer to the bill, and with the testimony of the defendants.

The answer states that in the tank were placed fat and water in equal quantities, and that during the operation the first charge of water was drawn off and a second charge of water introduced.

The defendant James N. Gamble testified that the barrels of glycerine obtained under the new process were 40-gallon barrels, containing, as he estimated, 330 pounds; and to the question, "Can you state what amount of water was used in each charge in the process as carried on from 1870 to 1875?" answered: "I cannot state positively from recollection of what was absolutely used. My recollection was, however, that it was in each charge about fifty per cent of the fat, and this recollection is confirmed by the amount of glycerine water obtained."

The amount of glycerine water obtained, as stated by the master from the defendants' books, was 65,312 barrels, which, at 330 pounds each, is 21,552,960 pounds. This is not half, but 92.4 per cent of 23,322,777, the number of pounds of fat treated by the defendants, as ascertained by the master from their books; and perhaps a somewhat, but not much, less proportion in bulk.

As to the old process, the defendant William A. Proctor, who was a member of the firm while they were using it, testified as follows:

Opinion of the Court.

"64. The saponifying tubs were large enough to contain about double the quantity of fat you put in them, I understand? Ans. They were.

65. About how much water was put into these tubs, along with the fat? Ans. A little less than the volume of the fat, so that the vats were almost full. It was calculated that the condensed steam would supply water enough to keep them full.

"66. When the cooking of the mass in the saponifying tubs was completed, the tubs were about full of lime soap and water, I understand? Ans. They were not full, there being space enough to allow for the boiling of the water without excessive flashing out; that was all. The water in the vat, when the operation was through, was about equal to the bulk of the fat that had been put in.”

Upon this testimony, as the whole of the glycerine could hardly have been separated from the mass of lime soap by merely drawing off, it may safely be concluded that the amount of glycerine water, obtained under the old process, which the witness speaks of as "about equal to the bulk of the fat that had been put in," was not more than 90 per cent of the fat treated, and that there was no substantial difference in this particular between the results of the two processes.

It is therefore clear that the old process would produce only one-half the amount of glycerine reported by the master and stated in table B; and that the sum of $61,701.77, at which the master has arrived by deducting from $103,143.03, the value of 65,312 barrels of glycerine water obtained under the new process, $41,441.26, the value of 130,624 barrels, as obtainable under the old process, must be increased by adding half of the amount deducted, or $20,720.63.

The findings of the master, upon which he bases his conclusion of the amount of loss of fatty acids in using the plaintiff's invention as compared with the old process, are shown by the following extracts from his report:

"It does not appear that saponification by water alone in such digesters" as the defendants used "had been regularly employed by any one; but the testimony shows that" those