DEPARTMENT OF TERRESTRIAL MAGNETISM. 309 



the author's observations on natives of northeastern Siberia while a member 

 of Captain Amundsen's Arctic Expedition on the Maud during 1919 to 1920. 

 Upon Captain Amundsen's suggestion, the author spent seven and one-half 

 months from September 1919 with a tribe living about 700 miles west of Bering 

 Strait, taking advantage of the unique opportunity afforded for gathering 

 information regarding this little-known tribe while the Maud was in winter 

 quarters. The author accompanied the tribe from its summer quarters at 

 Avon Island to its winter quarters in the sheltered forests in the interior, 

 rejoining the expedition in the spring. 



The scientific work of the present Amundsen Arctic Expedition. 1 H. U. Sverdrup. Jour. 

 Wash. Acad. Sci., vol. 12, 270-271 (June 4, 1922). 



An account was given of Captain Amundsen's Maud Expedition during 

 1918 to 1921 and of the results obtained, including magnetic observations 

 (see pp. 307-308), registrations of meteorological elements, tidal observations, 

 and information of ethnological interest obtained by the author during the 

 winter spent with the Chukchi tribe of northern Siberia. 



Because of necessary repairs, the vessel of the expedition had to proceed 

 in the summer of 1921 to Seattle. A brief account was also given of the 

 scientific program which it is hoped to carry out during the continuation of 

 the expedition's work beginning in July 1922. In addition to the magnetic, 

 atmospheric-electric (potential-gradient), polar-light, and meteorological ob- 

 servations, it is planned to make an extensive series of oceanographic deter- 

 minations and measurements of nocturnal radiation. It is expected also that 

 there will be some opportunity to take gravity observations over deep sea, 

 but under conditions similar to those in solid ground. Astronomical observa- 

 tions as necessary in connection with the determination of drift course and 

 geographical explorations will also be carried out. 



Hall effect and specific resistance of silver films. G. R. Wait, Phys. Rev., Vol. XIX, 615- 

 622 (June 1922.) 



This paper gives the results of an investigation carried out at the Physical 

 Laboratory of the State University of Iowa on the Hall effect and specific 

 resistance of silver films, 200 to 20 /jl/j. thick. In agreement with previous re- 

 sults, the specific resistance increased more and more rapidly with decreasing 

 thickness, becoming infinite for about 20 /x/jl. On the other hand, the Hall coeffi- 

 cient was found to be the same in the films as in the bulk metal. The thick- 

 nesses were computed from the weight of silver in each film, assuming the 

 density that of the bulk metal. The films were obtained by chemical 

 deposition. 



After discussing various proposed theories of electrical conduction in thin 

 films in the light of the above results, it is concluded that these and other 

 facts are in harmony with the simple conception that the film consists of 

 granules, each having the properties of the bulk metal, and that conduction 

 occurs only along strings of granules in contact. 



Exceptionally hard films whose resistance, instead of decreasing, increases 

 slightly with time, were obtained by using four times the amount of sodium 

 hydroxide specified in the Brashear method of depositing silver films. 



i Abstract of the following papers: The scientific work of the present Amundsen Arctic Expedi- 

 tion, read before the Meteorological Section of the American Association for the Advancement 

 of Science, Toronto, Canada, December 28, 1921, and before the Philosophical Society of Wash- 

 ington, March 11, 1922; Plans for the scientific work on Captain Amundsen's Arctic Expedition, 

 read before the Physics Club of the U. S. Bureau of Standards, Washington, D. C, February 

 20, 1922. 



