130 



Ruschenberger.] xu\j [Nov. 6, 



He visited the Mint at San Francisco, in 1873, departing from 

 Philadelphia August 5, and returning September 20, carefully- 

 studied its working, and submitted reports upon it to the 

 Director of the Mint in October and December. 



September 4, 1874, he reported the successful result of his 

 experiments made at the Assay Office in New York, in August, 

 to . rid the establishment of inconvenience 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, sometimes seriously annojnng neigh- 

 bors. 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 the 

 fuel these fumes promote its combustion, which is an interesting 

 chemical fact. 



He visited Washington by request in January and March, 

 1 875, to confer with the authorities about plans which he had 

 proposed for the equipment of a refinery in the Mint at San 

 Francisco. Those plans, which included the sulphuric acid pro- 

 cess recommended by him October 15, 1873, were adopted May 

 3, 1875. They included the erection of additional buildings. 



He arrived at San Francisco May 19. The actual work of 

 construction and equipment of the refinery was begun May 24, 

 and finished July 26, and placed in charge of the Superintendent, 

 in working order, August 25, 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 100,000 gallons of excellent water daily for 

 all the uses of the establishment. 



In reference to this enterprise, the Director of the Mint, in his 

 annual report, November 20, 1875, says: "The arranging of the 

 plan of the refinery and its equipment was intrusted to Robert 

 E. Rogers, Professor of Chemistry in the University of Penn- 

 sylvania, whose eminent qualifications as a chemist and metal- 

 lurgist, rendered him peculiarly qualified for this service, and 

 who performed the duty assigned him in an entirely satisfactory 

 manner. The refinery has been in successful operation since the 

 2(')th day of August last, and with much advantage to the public 

 interests." 



