198 REPORTS ON INVESTIGATIONS AND PROJECTS. 



of atmospheric refraction, to astronomical observations for determining a 

 ship's position. So, again, there have been obtained results of value to the 

 student of atmospheric electricity.* The Carnegie also contributes useful 

 meteorological data to meteorological institutions. In brief, every oppor- 

 tunity is embraced by the scientific personnel to obtain information of prac- 

 tical as well as of scientific value. 



From the detailed statements below of the field work, it will be seen that 

 the land work during the present fiscal year consisted in the satisfactory 

 completion of important work in Africa by Professors Beattie and Morrison, 

 who, as will be recalled, were associated with the Department during 1909, 

 and in Turkey and Asia Minor by Observers Pearson and Sligh. 



Of considerable importance for the rapid execution of land magnetic work 

 was the purchase of a 35-foot launch supplied with an 18 H. P. Remington 

 oil-engine for use along the rivers in the portions of South American coun- 

 tries where proper transportation facilities could not be readily had. This 

 expedition is in charge of Observer C. C. Stewart ; the launch, which is called 

 El Imdn (Spanish for the magnet) was shipped to Manaos, Brazil, from 

 which point Mr. Stewart started his work. 



Satisfactory progress, as will be seen from the detailed statement, has 

 likewise been made in the office work and in theoretical investigations. The 

 rapid reduction and publication of the results of the Carnegie has already 

 been noted. As a result of intercomparisons of magnetic outfits made by the 

 observers of the Department in all parts of the globe, it is now possible to 

 make a final publication of the magnetic data thus far obtained by the De- 

 partment, all reduced to a common basis ; the manuscript of this report is in 

 good state of progress and is rapidly approaching completion. 



In the workshop of the Department there have been constructed various 

 instruments of special design and of light weight, which promise to further 

 facilitate the field operations, especially in matter of transportation. 



Of theoretical interest are the results obtained with regard to magnetic 

 storms as published in recent issues of the journal "Terrestrial Magnetism 

 and Atmospheric Electricity." The main conclusions were as follows : 



Magnetic storms do not begin at precisely the same instant all over the 

 earth. Those beginning abruptly, in which the efifects are in general small, 

 appear to progress over the earth more often eastwardly, though also at 

 times westwardly, at a speed of about 7,000 miles per minute, so that a 

 complete circuit of the earth would require 3.5 to 4 minutes. For the 

 bigger and more complex magnetic disturbances the velocity of propagation 

 may be cut down considerably. The time of beginning of the disturbance 

 may be appreciably dififerent for the various magnetic elements, according 

 to the character of the disturbing causes. 



* See Observer Kidson's report, "Atmospheric electricity observations on the first 

 cruise of the Carnegie," Journal "Terrestrial Magnetism and Atmospheric Electricity," 

 June 1910. 



