18 abstracts: terrestrial magnetism 



ill 10,000, except for some possible error which n;ay be inherent in 

 the magnetometer-method but not yet disclosed. 



When the ocean work of the Department was begun in 1905, it was 

 necessary either to design entirely new, or to modify considerably, existing 

 devices. There have resulted thus new magnetic instruments, for use 

 at sea, designed, as well as chiefly constructed, by the Department. 

 With these instrumental devices, an accuracy in ocean magnetic work 

 has been secured which, under favorable conditions and devoting the 

 same time as in land work, does not fall much short of the general 

 accuracy of land field work. ' L. A. B. 



TERRESTRIAL' MAGNETISM.— i^eswZfs of magnetic observations 

 made by the U. S. Coast and Geodetic Survey in 1913. R. L. Faris. 

 U. S. Coast and Geodetic Survey Special Publication No. 20. 

 Pp. 52. 1914. 

 In 1882 the results of field magnetic observations made by the Coast 

 and Geodetic Survey prior to 1881, together with descriptions of sta- 

 tions, were published as Appendix 9, Report for 1881. In "Magnetic 

 Declination Tables and Isogonic Charts for 1902" declination results 

 were given for all stations occupied up to that time and descriptions 

 were given of stations established subsequent to 1881. From 1903 

 to 1911 there was published annually an appendix to the Superintend- 

 ent's report giving the results of the magnetic observations made 

 during the fiscal year (July to June) covered by the report. Special 

 Publication No. 15 contained the results of magnetic observations made 

 between July 1, 1911 and December 31, 1912. 



The present publication contains the results of observations made 

 on land and at sea during the calendar year 1913, and in the Philip- 

 pine Islands in 1912, together with descriptions of the stations occupied. 

 Results are given for 282 stations in 245 localities including a general 

 magnetic survey of the Philippine Islands, a detailed survey of the 

 crater of Kilauea, Hawaii, and an investigation of the area of local dis- 

 turbance in the vicinity of Wilmington, Delaware. A table is given 

 presenting a comparison of the declination results at 69 repeat stations 

 with the results of earlier observations in the same localities. The 

 results have been corrected to reduce them to the International Stand- 

 ard of the Department of Terrestrial Magnetism of the Carnegie In- 

 stitution of Washington. Horizontal Intensity results heretofore pub- 

 lished must be diminished by 1 part in 1000 to reduce them to that 

 standard. D. L. Hazard. 



