704 FEDBEAIi BBPOETER. �that the defendant saved, by uaing sueh infringing lamp, 2 16-100 gallons of whale or lard oil during each year, being a total saving of oil of 205 1-10 gallons, by comparing the quantity of kerosene oil which each infringing lamp burned in each year with the quantity of whale or lard oil which the smallest size of lamp burning it would consume in each year when used the same number of hours; and that the total value of such saving and advantage was $324.95. It also States that the defendant denied the further benefit, saving and advantage of using the cheaper kerosene oil, the value of such saving being the difference between the market priee of the kerosene oil used and the market price of an equal amount of the higher-priced oils which it would have been compelled to use but for its infringement ; that such saving amounted to $3,320.91 for ail the 11 lamps for the time they were so used; that the total value of the savings derived by the defendant from the use of the plaintiff's invention was $3,320.91; that ail railroad companies use head-light burn- ers on their engines; that the plaintiff possessed the facili- ties to manufacture ail the burners required by railroad com- panies in the United States, and could have fumished the defendant with any number of burners required by it had the defendant desired; that the plaintiff's lamp was, during ail the time of the infringement, the only one adapted to the burning of kerosene oil for head-light purposes, except infring- ing lamps; that the plaintiff's established price for his head- light burner was $15 each, and the cost of each was $2; and that the plaintiff was damage d by reason of said infringement by the defendant to the extent of $13 for each of the 11 infringing lamps which the defendant purchased from other parties, being in ail $143. �The defendant excepts to the report on the ground that the plaintiff has failed to show what profits the defendant made by the use of the patented improvements ; that the master ought not to have allowed the saving of the $224.95, or considered that matter; that he ought not to have allowed the saving of the $3,320.91, or considered that matter; that the finding that from December 19, 1865, to April 29, 1879, ����
