bought, wells were dug, and the 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. Linderman, by the Secretary of the Treasury, a committee to make examinations in the mint at Philadelphia for the purpose of ascertaining 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 experiments at the mint and at the Assay Office 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 Department of the Mint. This investigation, valuable in itself, was also valuable in its consequences, because it suggested modifications 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 annoying 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 concerning plans which he had proposed for the equipment of a refinery in the mint at San Francisco. The plans, which included a sulphuric-acid process recommended by him, and the erection of additional 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 hollow 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.