PROBLEMS OF TERRESTRIAL MAGNETISM 751 



pert in terrestrial magnetism requires a lifetime of exclusive devo- 

 tion and singleness of purpose, such as is requisite for success in any 

 of the older, well-recognized sciences. 



The magnetic ian must struggle to have accorded him equal 

 privileges and recognition with the astronomer, the astrophysicist, 

 the geologist, or the meteorologist. I am confident that the day is 

 not far off when even he who devotes his entire time and energies to 

 terrestrial magnetism will be obliged to specialize in this field also to 

 secure the best results, just as the physicist, for example, nowadays 

 must restrict himself to one definite branch of his entire subject. To 

 illustrate, the study of the secular variation of the earth's magnetism 

 is one sufficiently broad and extensive to occupy one's sole atten- 

 tion. Those of our eminent investigators who are only indirectly 

 interested in this branch of terrestrial magnetism are found to 

 deliver opinions regarding this phenomenon representing no advance 

 upon the ideas prevailing a half-century or a century ago. And thus 

 it happens that papers on the secular variation are even to-day 

 being presented to learned academies involving theories previously 

 advanced and exploded by both past and recent experience. 



The first problem, therefore, is to secure that proper recognition 

 of the study of the earth's magnetism as a subject of scientific 

 inquiry universally conceded as essential to the best success in 

 other sciences. A great advance in this direction must be recorded, 

 viz., that the Carnegie Institution of Washington, in full apprecia- 

 tion of this first and great need of magnetic research, has recently 

 established a department of Research in Terrestrial Magnetism on 

 an entirely independent footing from its other established depart- 

 ments, its operations embracing the entire globe. Here the great 

 problems of magnetic research, in cooperation with the leading 

 magneticians, can be studied not as subsidiary to some other great 

 branch of scientific inquiry, but by themselves, wholly apart from 

 any considerations of immediate economic value. 



The next great problem is to secure the necessary recognition of 

 the fact, among those advancing theories on any of the earth's 

 magnetic or electric phenomena, that in nearly every instance 

 sufficient data are not at hand for crucial and decisive tests of theory. 

 The cause of this is twofold: First, the observational data in 

 general have not the requisite extent and proper distribution either 

 in time or space or both; and second, the mathematical discussions 

 or analyses to deduce the facts from such data as may be at hand 

 are in most instances not complete or are entirely lacking, primarily 

 because of the inadequacy of the means necessary for such discussions 

 as these which involve much time and labor. Thus one of the great 

 questions of the day, one of liveliest interest to the astrophysicist 

 and to the meteorologist, as well as to the magnetician, the sub- 



