326 CARNEGIE INSTITUTION OF WASHINGTON. 



The section headings for the Carnegie works are in general the same, except 

 that, since the Carnegie is a non-magnetic vessel, the sections dealing with 

 the determination and discussion of deviation corrections are omitted. The 

 construction of the Carnegie in 1909 is described and illustrated. The 

 synopses of cruises are for the period 1909-1916 (September). 



A special feature of the Carnegie work is the full account of the new instru- 

 ments devised bj" various members of the Department of Terrestrial Mag- 

 netism, and constructed in the Department's instrument-shop. Thus there 

 are descriptions and illustrations of the marine collimating-compass for mag- 

 netic declination, the sea deflector for horizontal intensity and declination, 

 the sea dip-circle for inclination and total intensity, the marine earth-inductor 

 for inclination, and a reversible gimbal stand. The descriptions also give 

 the scheme or method of observation with each instrument. 



The section on geographic position at sea is given special treatment under 

 the Carnegie work, and specimens of observations and computations are added. 



A brief account is given also of special investigations, fuller publication 

 being reserved for a future volume. The tests made from time to time 

 showed the absence, for the Carnegie, of any deviation corrections large 

 enough to require being considered. A general statement, accompanied by 

 diagrams, is made regarding the extent and character of the corrections 

 which the existing magnetic charts require in order to make them conform 

 to the observations on the Galilee and the Carnegie. 



Under extracts from the commander's field reports are found, among other 

 matters, notes on the occurrence of thunder at sea as observed on the Carnegie's 

 cruise, 1915-1916, and an account of the Carnegie's sub-Antarctic voyage, 

 1915-1916. The special reports deal with the results of the atmospheric- 

 electric work on board the Galilee, 1907-1908, and on the Carnegie, 1909-1916 

 (April) and contain some discussions concerning magnetic chart corrections 

 and secular variations of the magnetic elements. 



Results of atmospheric-electric obsen^ations made aboard the Galilee (1907-1908) and the 

 Carnegie (1909-1916). L. A. Bauer and W. F. G. Swann. (One of the "Reports 

 on Special Researches "contained in "Ocean Magnetic Observations," 1905-1916.) 



The paper commences with an Introduction by L. A. Bauer, in which are 

 summarized the considerations which govern in determining the extent of the 

 program of scientific work possible aboard such vessels as the Carnegie and 

 Galilee. The importance of speedy reduction and discussion of accumulated 

 scientific data is emphasized, so that information as to the direction in which 

 the observations are leading may follow closely upon the observations them- 

 selves. References are cited showing that the pioneer investigators in atmos- 

 pheric electricity strongly urged the foundation of a world-wide atmospheric- 

 electric survey, especially when such could be undertaken in conjunction with 

 a magnetic sui'vey. The Introduction concludes with a brief historical sketch 

 of the development of the atmospheric-electric work of the Department of 

 Terrestrial Magnetism. 



Next is given a compilation of the main atmospheric-electric results obtained 

 at sea by the Department since 1907, as based on the field reports. The 

 details of the work up to the end of the Carnegie's third cruise in 1914 have 

 already been published in various papers in the Journal of Terrestrial Mag- 

 netism and Atmospheric Electricity, and abstracts have appeared in previous 

 annual reports. 



A greatly increased program of atmospheric-electric work was undertaken 

 on the Carnegie's fourth cruise (1915-1916), and the paper contains a full 



