PHYSICS — BURGESS, CAMPBELL. 



249 



The analyses which have thus far been made may be summarized 

 in the following- table : 



Per cent. 

 Carbon 0.00221 to 0.0084. 

 Silicon o. to 0.0268. 



Sulphur o. to 0.0008. 



Phosphorus, arsenic, manganese, copper, nickel, cobalt, calcium, and 

 magnesium absent. 



Much time has been given to the problem of melting the iron with- 

 out introducing impurities. This involved an extensive study of 

 refractory materials and different methods of furnace construction. 

 We have recently succeeded by means of a specially designed furnace 

 in melting the iron contained in a graphite crucible lined with a mag- 

 nesia cement. The following analyses show the impurities in the iron 

 before and after melting : 



A preliminary study of electrolytic iron under various methods of 

 treatment has been made by means of a microscope, and some interest- 

 ing micro-photographs showing the structure of electrolytic iron are 

 given in the full report. The production of iron alloys has only 

 recently been taken up, and the results can not therefore be given in 

 this report. 



Campbell, "William, Columbia University, New York, New York. 

 Grant No. 179. Sttidy of the effect of heat treatment upon the 

 microstructure and physical properties of steel and iron. (For first 

 report see Year Book No. 3, p 124.) $1,500. 



Abstract of Report. — The research upon the " Heat treatment of 

 some high carbon steels" has been continued by a microscopic 

 examination of the series heated to given temperatures from 6oo° 

 to 1200 C. In addition the structures of the steels when subjected 

 to quenching have been examined. The main point of interest hinges 

 upon the breaking down of the carbide of iron cementite into free 

 iron ferrite and graphite in the neighborhood of 1000 C, and in the 

 formation of white cast-iron around the grains of steel when the tem- 

 perature approaches the melting-point. 



