354 schaller: mineralogical notes 



fically any of the characteristics defined by these three methods 

 of examination, either with the temperatures of rolhng here 

 observed or with each other. 



The following thermal properties of these rail steels were de- 

 termined in the laboratory: The critical range on heating is 

 located (maximum) to within 7°C. of 732°C. (1350°F.) for the 10 

 samples of O.H. and Bessemer steels examined. On cooling, 

 the critical range lies between the limits 680°C. (1256°F.) and 

 650°C. (1202°F.). The melting or freezing range for rail steel 

 extends from about 1470°C. (2680°F.) to nearly the melting point 

 of iron, located at 1530°C. (2786°F.). 



The expansion for O.H. and Bessemer steels is not the same. 

 Above 800°C. (1470°F.) the expansion for both increases linearly 

 with temperature, and the linear coefficient per degree centigrade 

 has the following mean values between 0° and 1000°C. : 



(1) For Bessemer Steel (Carbon .40 to .50 per cent): a = 0.0000146 



(2) For Open Hearth Steel (Carbon .65 to .70 per cent) : a = 0.0000156 

 to 0.0000161. 



The average composition of the Bessemers was carbon = 0.40 

 to 0.50 and maganese = 0.76 to 0.93; of the Open Hearths, car- 

 bon = 0.65 to 0.70 and manganese = 0.66 to 0.72. 



In 1909 the American Society for Testing Materials limited 

 the shrinkage allowance on 100 lb. sections to 6f inches in 33 

 feet, or to an equivalent of 1947°F. (1064°C.) for O.H. and 

 2055°F. (1124°C.) for Bessemer rails, a specification which is still 

 in force. Such a shrinkage clause, therefore, does not serve the 

 avowed purpose of limiting the finishing temperatures to a value 

 slightly above the critical range. 



MINERALOGY. — Mineralogical notes, Series 3. Waldemar 

 T. Schaller, U. S. Geological Survey. 



A bulletin with this title has been submitted for publication by 

 the U. S. Creological Survey. In order to secure priority, the 

 following very brief abstracts are given of the original papers : 



Koechlinite {Bismuth Molybdate), A New Mineral from Schnee- 

 berg. Saxony, is named after Dr. Rudolf Koechlin of Vienna. 

 The orthorhombic (a : b : c = 0.9774 : 1 : 1.0026) crystals are 



