ABSTRACTS 



Authors of scientific papers are requested to see that abstracts, preferably 

 prepared and signed by themselves, are forwarded promptly to the editors. Each 

 of the scientific bureaus in Washington has a representative authorized to for- 

 ward such material to this journal and abstracts of official publications should 

 be transmitted through the representative of the bureau in which they originate. 

 The abstracts should conform in length and general style to those appearing in 

 this issue. 



PHYSICS. — The density and thermal expansion of linseed oil and tur- 

 pentine. H. W. Bearce. Bulletin of the Bureau of Standards. 

 1912. 

 Sixteen samples of linseed oil and twelve samples of turpentine were 

 examined with a view to determining their physical and chemical charac- 

 teristics; special attention was given to the density and thermal expansion. 

 Tables have been prepared for obtaining the densities of these sub- 

 stances at temperatures between 10° and 40° C. from their densities at a 

 single temperature; also conversion tables for changing pounds to 

 gallons and gallons to pounds. H W. B. 



PHYSICAL CHEMISTRY. — Preliminary report on the ternary system 

 CaO — A1 2 — SisCV A study of the constitution of Portland cement 

 clinker. E. S. Shepherd and G. A. Rankin, with optical study by 

 Fred. E. Wright, Geophysical Laboratory. Journal Industrial 

 Engineering Chemistry, 3: 1. 1911. 

 In the earlier work with mixtures of pure lime and silica, two com- 

 pounds, the metasilicate (CaO.Si0 2 ) and the orthosilicate (2CaO.Si0 2 ), 

 were definitely established, but no trace of the hitherto generally accepted 

 tricalcic silicate (3CaO.Si0 2 ) could be found in mixtures of pure lime 

 and pure silica. In the three-component system, on the other hand, the 

 tricalcic silicate appears promptly with the addition of alumina to mix- 

 tures of appropriate lime-silica concentration, and after a long and diffi- 

 cult experimental investigation, involving the study of about 1,000 heat 

 treatments of various compositions, many of which required to be stud- 

 ied at temperatures between 1800° and 1900° C, it has finally been 

 prepared pure, excepting for a small excess (between 1 and 2 per cent) 

 of orthosilicate or lime or both. 



Tricalcic silicate appears to be unstable at its melting temperature, 

 and so does not form from a melt of this composition. For the same 

 reason, it does not form eutectics with the adjacent compounds, calcium 



7 



