DEPARTMENT OF TERRESTRIAL MAGNETISM. 313 



of ten or more. If efforts, backed by eminent persons and influential 

 scientific assemblies, have been so unsuccessful, even during a period 

 of no war, what may be expected, under the present conditions, during 

 the next decade or two? 



When one looks into the geographical distribution of the existing 

 cosmophysical observatories, the first fact, immediately obvious, is 

 that the scientific requirements have been most inadequately fulfilled. 

 Too frequently mere living conveniences, or purely local reasons, have 

 been allowed to govern the selection of a site. For one reason or 

 another, no European country has been able to establish its magnetic 

 observatories on the same broad principles as those which governed 

 the estabUshment of the magnetic observatories of the United States 

 Coast and Geodetic Survey. Some of the leading European nations, 

 while having within the borders of the home country a greater number 

 of observatories than are scientifically necessary, have established either 

 no observatories in their colonial possessions, or insufficiently support 

 such as exist. Indeed, the conditions permitted at certain of the estab- 

 lished observatories are surprising. 



About one-half of the 45 existing magnetic observatories are located 

 in Europe; 39 of them are in the Northern Magnetic Hemisphere, 

 hence but 6 in the opposite hemisphere, and at two-thirds of the south- 

 ern stations the conditions are such that the observatories can not be 

 ranked as first grade. 



To prepare for the improvement of existing conditions, as far as may 

 lie within the power of the Department by the means provided, a 

 division, known as the Observatory Division, was created on June 1, 

 1915, and certain preliminary plans and investigations were undertaken. 

 It is hoped that it may be found possible for the Department in the 

 near future to erect, man, and equip at least two cosmophysical observa- 

 tories at points in the Southern Hemisphere where they are most needed. 



It should be recalled that the adequate solution of all the problems 

 connected with the mapping of the Earth's magnetic state at any given 

 time involves also the adequate accomplishment of the second task here 

 discussed. 



MAGNETIC SURVEY OF THE OCEANS. 



After the completion of the third cruise of the Carnegie, described in 

 the report of last year, she was out of commission for a few months, 

 during which time an observatory was built, just abaft the after dome, 

 for the housing of the instruments used in the measurements of the 

 electrical state of the atmosphere. An additional stateroom was pro- 

 vided for the accommodation of an extra observer. The bottom of 

 the vessel was sheathed with a copper alloy, and a belt, consisting of brass 

 plates, was added to afford some protection against the ice-conditions 

 likely to be encountered on the next cruise. 



