224 REPORTS ON INVESTIGATIONS AND PROJECTS. 



MINERAL SOLUTION AND FUSION UNDER HIGH TEMPERATURES 



AND PRESSURES. 



Arthur L.Day, U. S. Geological Survey, Washington, D. C. Grant 

 No. 225. (For first report see Year Book No. 3, p. 80.) $15,000. 

 At the time of the last annual report the laboratory rooms had 

 been occupied only three months, and nearly all of our energies and 

 resources were being concentrated upon the designs and construc- 

 tion of the permanent plant. A considerable portion of the work 

 of this year and of the allotment has necessarily been devoted to the 

 same purpose. About one-fourth of the sum ($15,000) allotted to 

 this research during the present year has been applied to the perma- 

 nent plant, $8,200 has been expended in salaries, and the balance for 

 running expenses of the laboratory and the director's visit to some 

 of the leading laboratories of Europe. 



The scope of the plant and its expected usefulness were described 

 at some length from the plans in my previous report, and these plans 

 have been followed with but little deviation. 



THE POWER PLANT. 



We have installed during the year as a part of the power plant and 

 workshop : 



(i) An alternating current plant of about 30 horsepower, suitable for the gener- 

 ation of current for high temperatures, and an auto transformer in which a 

 very wide range of regulation iS provirled for. 



{2) A 15-horsepower electrically-driven air-compressor capable of delivering air 

 or some other gas to the laboratory room under a pressure of 500 pounds. 



(3) An electrically-driven vacuum-pump for exhausting reasonably large spaces 



rapidly. 



(4) A small blast-motor for delivering large volumes of air to the gas-furnaces 



under a pressure of about lo pounds. 



(5) A powerful vertical drill-press for the workshop. 



Basement space was furnished by the Survey during the past winter 

 for mounting the heavy machines. Suitable connections leading to 

 the laboratory had been provided at the close of the previous year. 



NEW LABORATORY EQUIPMENT. 



New apparatus has also been mounted in the laboratory, as follows : 



(i) A gas thermometer for an original determination of the fundamental scale 

 of temperature above the existing scale, which extends only to 1150° C. 

 Almost all the temperatures used in mineral work lie above this limit. 



(2) Sevt-ral resistance furnaces arranged for melting minerals under conditions 



which not only admit of temperature measurements, but of the control of 

 the atmosphere and its pressure during melting or solidification. 



(3) A resistance furnace for use with the gas thermometer, iii which especially 



exact control of the conditions of measurement is provided for. 



