ABSTRACTS 



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 this issue. 



TERRESTRIAL MAGNETISM.— Results of observations made at the 

 United States Coast and Geodetic Survey Magnetic Observatory at 

 Cheltenham, Md., 1918 and 1914- Daniel L. Hazard. U. S. 

 Coast and Geodetic Survey Serial Publication No. 19. 1915. 

 This publication is in continuation of the series giving the results 

 obtained at the Cheltenham magnetic observatory since its estab- 

 lishment in 1901 . It contains a summary of the monthly determinations 

 of the scale-values of the horizontal intensity and vertical intensity 

 variometers; the base-line values derived from the weekly absolute 

 observations; diurnal variation tables for the magnetic elements D, 

 H, and I, the total force F, and the rectangular components X, Y, Z; 

 hourly values of D, H, and Z, together with daily and hourly means 

 for each month; a tabulation of the earthquakes recorded on the seis- 

 mograph; a list of the magnetic disturbances of considerable magni- 

 tude and reproductions of the magnetograms showing the more marked 

 disturbances. Attention is called to the fact that beginning with 1913 

 intensity results obtained by this Bureau have been reduced to the in- 

 ternational standard of the Department of Terrestrial Magnetism of 

 the Carnegie Institution of Washington. Published results for earlier 

 years must be diminished by one part in a thousand to reduce them 

 to that standard. 



D. L. H. 



GEOLOGY. — A peculiar oolite from Bethlehem, Pennsylvania. Edgar 



T. Wherry. Proceedings of the U. S. National Museum, 49: 



153-156, pi. 40-41. Aug. 13, 1915. 



The material described occurs in a quarry in magnesian limestone. 



In one layer the ooids are divided parallel to the bedding into a light 



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