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 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. — Wheatstone bridges and accessory apparatus for resistance 

 thermometry. E. F. Mueller. Bureau of Standards Scientific 

 Paper No. 288 (Bull. Bur. Stds., 13: 547). 1916. 



A type of Wheatstone bridge, suitable for use in resistance ther- 

 mometry, has been developed, in which plugs or dial switches are used, 

 and the circuits so arranged that the errors due to contact resistances 

 are no greater than with the mercury contact bridges heretofore used. 

 With a comparatively simple and inexpensive type of apparatus it has 

 been possible to attain the high degree of precision and accuracy de- 

 manded in modern work with resistance thermometers. 



A method of measuring potential terminal resistances by the Wheat- 

 stone bridge method is also given, and the necessary accessory appa- 

 ratus for this purpose is described. E. F. M. 



PHYSICS. — The damping of waves and other disturbances in mercury. 

 M. H. Stillman. Bureau of Standards Scientific Paper No. 289 

 (Bull. Bur. Stds., Vol. 13). 1916. 



In instruments involving the use of mercury, the waves and other 

 disturbances, produced by the unsteadiness of the containing vessel, 

 are a frequent source of trouble. If the mass of mercury be subjected 

 to a strong magnetic field, the direction of the field being approxi- 

 mately at right angles to the direction of motion of the mercury, these 

 motions will be strongly damped. 



The substitution of a non-magnetic metallic container for a glass 

 container greatly increases the magnitude of the damping. 



It is suggested that this method might sometimes be used when it 

 is desired to obtain accurate adjustments of mercury surfaces at sea 

 and in other places where unsteadiness of the mercury container is 

 unavoidable. M. H. S. 



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