578 abstracts: technology 



SOIL PHYSICS. — Hydrogen-ion concentration measurements of soils 

 of two types: Caribou loam and Washburn loam. Louis J. Gillespie 

 and Lewis A. Hurst. Soil Sci. 4: 313-319. 1917. 



The Caribou loam and the Washburn loam from Aroostook County, 

 Maine, possess before cultivation broadly different biological character- 

 istics. Both types are largely devoted to potato culture, the Caribou 

 loam being better adapted to this than the Washburn loam. 



Cultivated soils of the Caribou-loam type exhibit, when examined by 

 the colorimetric method, considerably greater hydrogen-ion concen- 

 trations than do soils of the Washburn-loam type. The average hy- 

 drogen-ion exponent for the Caribou soils was found to be 5.2; that of 

 the Washburn loam, 5.9. 



The possibility is indicated that the relative freedom of the Caribou 

 loam from potato scab may be due to its greater hydrogen-ion con- 

 centration. L. J. G. 



TECHNOLOGY. — Comparative tests of chemical glassware. Percy H 

 Walker and F. W. Smither. Bur. Stands. Tech. Paper No. 107 

 Pp. 23. 1918. 



Beakers of Kavalier glass, and beakers and flasks of Macbeth Evans, 

 Pyrex, Jena, Nonsol, Fry, and Libbey glasses were tested for chemical 

 composition, coefficient of expansion, refractive index, strain, behavior 

 on repeated evaporation, resistance to heat and mechanical shock, and 

 to solution in a variety of chemical reagents. 



No conclusions as to the relative values of the different wares can be 

 drawn from the chemical analyses, though these analyses may be useful 

 by enabling the chemist to choose a glass which will yield no objectional 

 ingredient to the solutions used in any particular piece of work. The 

 coefficient of expansion of all the glasses is low and is unusually so in 

 the Pyrex ware. All the ware shows more or less strain, but it was disap- 

 pointing to find that no information as to liability to break under sudden 

 changes in temperature or mechanical shock could be obtained by an ex- 

 amination for strain. All the ware tested showed good resistance to 

 repeated evaporation of a salt solution. The Kavalier ware is unsatis- 

 factory as regards solubility in water; all the other wares appear satis- 

 factory in this respect. All the ware is resistant to acids. Kavalier 

 is least resistant to carbonated alkalies, Pyrex more resistant than Kav- 

 alier but less resistant than the others. All the glasses are much attacked 

 by evaporating caustic alkalies. The authors are of the opinion that 

 considering all the tests each of the American wares is superior to the 

 Kavalier and equal or superior to the Jena ware. F. W. S. 



