April 14, 190.5.] 



SCIENCE. 



595 



years. Thanks to the awakening and re- 

 newed interest in magnetic work shown on 

 all sides, I fully believe that this hope will 

 be realized. 



The matter of prime consideration in mag- 

 netic work at sea is the elimination of the 

 effects resulting from the ship's own magnet- 

 ism as due to her construction and equipment. 

 Such effects are especially troublesome to 

 eliminate when it is proposed to obtain not 

 only the magnetic declination at sea, but also 

 the other magnetic elements (the dip and the 

 intensity of the magnetic force). The plan, 

 therefore, to be attempted this year, as worked 

 out by Mr. G. W. Littlehales, hydrographic 

 engineer of the United States Hydrographic 

 Office and consulting hydrographer of the 

 Department of Terrestrial Magnetism of the 

 Carnegie Institution, is in brief as follows: 

 " To charter a wood-built, non-magnetic, sail- 

 ing vessel of about six hundred tons displace- 

 ment, which, starting out in summer from San 

 Francisco, shall pursue a clockwise spiral 

 course embracing the entire North Pacific 

 Ocean. The object of planning such a course 

 is to gain continuous advantage throughout 

 the survey of the dynamical agencies of the 

 atmosphere and the ocean, in passing in suc- 

 cession into each of the five-degree quad- 

 rangles into which the chart* is divided and 

 in which observed values of the three magnetic 

 elements need to be obtained. 



" The seasonal shifting of the permanent 

 centers of barometric pressure will cause a 

 variation from month to month of the condi- 

 tions of wind and current that are repre- 

 sented on this particular chart, but if the 

 departure from San Francisco be taken in 

 the summer, the chain of meteorological 

 events will contribute toward the maximum 

 progress over the course, passing thence along 

 the west coast of America to the vicinity of 

 the Galapagos Islands, thence across the Pa- 

 cific in latitude between two and three de- 

 grees north, thence along the eastern side of 

 the Philippine Archipelago and !he empire of 

 J apan, thence eastward in about latitude fifty- 

 two degrees north, thence to the latitude of 



* Tlie course to be followed was shown in red 

 ink on a U. S. Hydrographic Office Pilot Chart of 

 the North Pacific. 



San Francisco, and thence continuing through 

 the series of areas bounded by parallels of 

 latitude and meridians of longitude each five 

 degrees apart, lying next on the midocean 

 side of the circuit last made, and proceeding 

 gradually and by successive circuits into the 

 central region of the North Pacific." 



The total length of the course marked out 

 is about 70,000 knots; however, each of the 

 first circuits practically closes at San Fran- 

 cisco, so that, if it is found that the method 

 pursued is not the best, the work can readily 

 be terminated or modified. From inquiries 

 made, it would appear that the entire work of 

 observation and reduction can be accom- 

 plished in three years. The cost per month 

 of the field work, inclusive of all expenses and 

 services, will approximate $1,500. Counting 

 eight months of continuous service per annum, 

 the total annual outlay is estimated at about 

 $12,000. 



This project as the result of careful consid- 

 eration and solicitation of expert opinion is 

 believed to be thoroughly feasible. It permits 

 of useful comprehensive results being imme- 

 diately obtained, and is one which can be in- 

 terrupted without any important waste of 

 antecedent expense, whenever circumstances 

 may render a discontinuance or a modifica- 

 tion of the original plan advisable. 



The region it is proposed at present to sur- 

 vey fortunately contains magnetic observa- 

 tories in requisite number and proper dis- 

 tribution for furnishing the necessary correc- 

 tions to be applied to the observed magnetic 

 elements in order to reduce them to a common 

 epoch. Thus continuous records of the mag- 

 netic variations required for this purpose will 

 be available from the following stations: 

 Sitka, Mexico, Honolulu, Manila, Shanghai, 

 Tokio. In addition .it is hoped that there 

 may be soon a magnetic observatory in Cali- 

 fornia or vicinity for lending effective co- 

 operation, and that the German government 

 will continue its magnetic observatory at Apia 

 throughout the period of the survey. Also 

 excellent opportunities for controlling instru- 

 mental constants and obtaining required addi- 

 tional data will be afforded by stations on the 

 coasts and on islands. 



