26 HEYL— PLATINUM IN NORTH CAROLINA. [February 7, 



At an early stage of the assaying work it was recognized that to 

 carry out such work in the laboratory of an industrial works devoted 

 to the working and refining of platinum on a large scale was a matter 

 of some delicacy. The obvious way to guard against infection was 

 to run blanks, and this was done with perfect success for eight 

 months. At the end of that time the furnace in which the assays 

 were made began to show signs of infection from the fine platinum 

 dust that might be detected almost anywhere in the works, and the 

 blank assays began to give minute traces of platinum. A new fur- 

 nace was then installed in another room, and satisfactory blanks 

 were again obtained. It was not considered prudent' to do much in 

 the way of sending out samples to other laboratories for check anal- 

 yses, but such check assays were made in our own laboratory by 

 Dr. Harry F. Keller, of Philadelphia, and the results agreed quite 

 well with our own figures. As an illustration of the care that was 

 taken to avoid false results, the air supply of the furnace was ex- 

 amined. The furnace was fired by gas mixed with air supplied from 

 a blower in a distant room. This blower supplied air to all parts of 

 the establishment, and its intake w^as not above suspicion. A glass 

 tube filled with cotton wool was fastened to one of the air cocks and 

 the air allowed to blow through it for two weeks. The cotton was 

 then burned and the ash examined for platinum. None was detected. 



The examination of the ground was carried out by our mining 

 engineer, Mr. James W. Neill, with great thoroughness. Samples 

 were taken over an area of six or seven square miles in the imme- 

 diate vicinity of the Klondike, and the peculiar rock of the region 

 was traced fifteen miles north, to Danville, Virginia, and fifty miles 

 south, to a point near Cedar Falls, N. C, and traces of platinum 

 were occasionally detected in it. The work lasted a year, and was 

 completed by an examination of the watershed of the region for 

 placers. This latter piece of work was done by Mr. John A. Ritter, 

 and extended far and wide, in the case of one river to a point two 

 hundred miles from Rufiin. In this examination traces of platinum 

 were found in the sands of the James river two miles west of Rich- 

 mond ; in the Dan river, where it is joined by Hogan's creek, which 

 drains the Rufifin region; in the Dan river at Danville, Va. ; in the 



