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 forward 

 such material to this journal and abstracts of official publications should be trans- 

 mitted 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. 



ELECTRICITY. — Copper wire tables. Circular Bureau of Standards 

 No. 32. 1911. 



This circular was prepared at the request of the Standards Committee 

 of the American Institute of Electrical Engineers. In its preparation 

 the Bureau has had the cooperation of that Committee and the tables 

 have been adopted as official by the Institute. 



The circular discusses the results of work recently completed at the 

 Bureau on the temperature coefficient and the conductivity of copper, 

 as well as previous standard values, and gives a history of wire gages, 

 showing that the trend of practice is toward expressing diameter directly 

 in decimal fractions of an inch. 



There are fifteen tables including complete reference tables for stand- 

 ard annealed copper, American Wire Gage, both in English and in metric 

 units; and similar abbreviated "working tables." There are also tables 

 for bare concentric cables of standard annealed copper and for hard- 

 drawn aluminum wire. The tables also include comparisons of wire 

 gages, and tables of temperature reductions, with complete explanations. 



Four appendixes give additional information — the first on the units 

 used in the expression of resistivity; the second on the calculation of the 

 "resistivity-temperature constant" and on the expression of the tem- 

 perature coefficient; the third on the density of copper; and the fourth 

 on the calculation of the resistance and mass per unit length of cables. 



J. H. Dellinger. 



AGRICULTURAL PHYSICS.— Studies in soil physics. E. E. Free. 

 Plant World, 14: Nos. 2, 3, 5, 7 and 8. 1911. 



These five articles present briefly and in a non-technical way the 

 author's point of view toward certain of the more salient points of soil 



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