SKETCH OF ROBERT EMPIE ROGERS. 839 



bought, wells were dug, and tlie work was carried on for some 

 time without profit ; and finally, in 1873, the whole concern was 

 sold out, a nearly total loss to the shareholders. Prof. Rogers 

 was the largest holder, having one fifth of the shares, and lost 

 more than any of the others. 



In 1872 Prof. Rogers was appointed, with Dr. H. R. Linder- 

 man, by the Secretary of the Treasury, a committee to make ex- 

 aminations in the mint at Philadelphia for the purpose of ascer- 

 taining the extent and sources of a waste of silver that was 

 alleged to be taking place there " in excess of the amount tolerated 

 by law." The processes of assaying and refining the bullion and 

 converting it into coin were carefully tested by numerous experi- 

 ments at the mint and at the Assay Ofiice in New York. About 

 two months were spent in the examination. The result of it was 

 presented July 25, 1873, in a well-considered and elaborate Report 

 on the Wastage of Silver Bullion at the Melter and Refiner's De- 

 partment of the Mint. This investigation, valuable in itself, was 

 also valuable in its consequences, because it suggested modifica- 

 tions in the method of refining the precious metals which were 

 afterward adopted. The Director of the Mint said in his annual 

 report that the results obtained were conclusive of several points, 

 and would be valuable in future minting operations. Prof. Rogers 

 next made an examination of the working of the mint at San 

 Francisco, concerning which he reported to the Director of the 

 Mint. In 1874 he experimented at the Assay Office in New York 

 concerning means of ridding the establishment of inconveniences 

 suffered from acid vapors. " Prior to that time nitrous-acid fumes, 

 arising from the nitric acid used in refining silver, were allowed 

 to escape through the chimney into the open air, seriously annoy- 

 ing neighbors. To correct the evil. Dr. Rogers had constructed 

 in the attic of the building a furnace for burning coke, into which 

 the fumes were conveyed and burned." Instead of extinguishing, 

 these fumes promoted the combustion of the fuel. He afterward 

 conferred with the Treasury authorities in Washington concern- 

 ing plans which he had proposed for the equipment of a refinery 

 in the mint at San Francisco. The plans, which included a sul- 

 phuric-acid process recommended by him, and the erection of ad- 

 ditional buildings, were carried out under his supervision, and 

 the completed work was put in charge of the superintendent in 

 August, 1875. "At the suggestion of Dr. Rogers during the 

 progress of the work, an artesian well was sunk within the hol- 

 low square of the mint, which supplies one hundred thousand 

 gallons of water daily for all the uses of the establishment." 

 The succeeding report of the Director of the Mint mentions the 

 advantage to the public interests which attended the operation 

 of the refinery. In connection with this work in the mint Prof. 



