322 CARNEGIE INSTITUTION OF WASHINGTON. 



mcnts used have been improved from time to time; about 150 magnetic pub- 

 lications and a large number of magnetic charts of various kinds have been 

 issued.^ It may, therefore, be said that the contributions of the Coast and 

 Geodetic Survey to the advancement of our knowledge in terrestrial mag- 

 netism have been unexcelled by any other national organization. 



From the earliest days of the Survey, magnetic obsei-vations were con- 

 sidered a legitimate and useful part of its work. In 1899 an enlarged annual 

 appropriation of $25,000 (about ten times the average annual amount pre- 

 viously allotted), made it possible to carrj' out a magnetic survey of the 

 whole United States on a more systematic basis and with greater expedition 

 than had theretofore been possible. The plan adopted for the reorganized 

 magnetic work of the Survey, on the basis of which the increased appropria- 

 tion was made, was that submitted by L. A. Bauer in March 1899, at the 

 request of the then Superintendent, H. S. Pritchett, who established on 

 May 1, 1899, a new division, known as the Division of Terrestrial Magnetism. 

 The chiefs of this Division have been: L. A. Bauer, 1899-1906; R. L. Faris, 

 1906-1915; and A. Braid, 1915-16. The present chief is D. L. Hazard, who 

 was connected with the Division as computer from the date of its establish- 

 ment. During the period 1900 to 1903, five magnetic observatories were 

 established, in connection with which effective and skillful aid was rendered 

 by J. A. Fleming, then aid in the Survey, now a member of the Department 

 of Terrestrial Magnetism. 



The year 1903 marks the inauguration of systematic magnetic observa- 

 tions at sea on the Survey vessels. During a trip made by L. A. Bauer, as 

 inspector of magnetic work, from Baltimore to Porto Rico, on the Blake, then 

 in command of Captain R. L. Faris, the present assistant superintendent, 

 magnetic obsei-vations, comprising the magnetic declination, the dip, and the 

 intensity of the magnetic force, were made daily at sea with the aid of newly 

 installed instrumental appliances. This experience, as well as that later 

 obtained in the conduct of the work, assisted L. A. Bauer in no small measure 

 in the inauguration of the magnetic survey of all the oceans under the auspices 

 of the Carnegie Institution of Washington. 



In conclusion, the chief results were set forth respecting the secular changes 

 of the magnetic elements in the United States. For no land area of similar 

 size can the secular changes of the Earth's magnetism be so comprehensively 

 and so accuratelj^ investigated as for the United States. This is in view of 

 the circumstance that the magnetic survey of the United States has been 

 going on with unbroken continuity for well-nigh three-quarters of a century, 

 and not at irregular intervals, as has been the case in other countries. 



Relation between changes in solar activity and the Earth's magnetic activity, 1902 to 1914. 

 L. A. Bauer. Science, n. s., vol. 43, 724 (May 19, 1916). New York. (Abstract 

 of paper presented before the American Philosophical Society, Philadelphia, April 

 14, 1916.) 



No criterion of solar activity, whether it be the spottedness of the Sun or 

 the faculse, prominences, or calcium flocculi, has been found to synchronize 

 j-trecisely with any quantity used as an index of the Earth's magnetic activity. 

 Thus, for example, the maximum magnetic activity in 1892 preceded the 

 maximum sun-spot activity of that period by a year. So, again, the recent 

 minimum magnetic activity of the Earth seems to have occurred in 1912, 

 whereas the minimum sun-spot activity did not take place until 1913, or a 

 year later. 



'Nearly one-third of the publication.s have appeared during the period 1899-191.'). 



