258 



SCIENCE 



[N. S. Vol. L. No. 1289 



Three specific research projects presented by 

 letter by Mr. E. A. Daly were then considered, 

 which may be briefly entitled : " (1) A Sys- 

 tematic Thermometric Study of the Gulf 

 Stream, (2) Improving of the Deep Sea 

 Thermograph, and (3) Continued Study of 

 the Composition of Volcanic Gases." These 

 were referred to the Executive Committee. 



A brief outline of a statement of the prob- 

 lems of seismology was given by Mr. Wood. 

 This document was referred to the delegation 

 to Brussels and to the Executive Committee. 



Mr. Bowie read a brief statement on isostasy 

 and its relationships. 



Mr. Bigelow made mention of work planned 

 for exploration in the Iforth Atlantic and the 

 desirability of having this undertaking af&li- 

 ated with the International Geophysical Union. 



Mr. Marvin made reference to the need of 

 centralization in the work of meteorological 

 bureaus, and internationally. 



Harry 0. Wood, 

 Acting Secretary 



appendix: report op the committee on investi- 

 gation OP EARTH TIDES 

 To the American Section of the International Geo- 

 physical Union: 

 Your Committee on Earth Tides begs to report 

 as follows: 



1. Meeommendation. — It is recommended that 

 earth-tide experiments be carried out as soon as 

 possible at stations in (1) Pasadena, California; 

 (2) some island in the central Pacific; (3) the in- 

 terior of Argentine; (4) England; (5) the inter- 

 ior of Africa; and also, if possible, (6) the in- 

 terior of India; (7) Japan; (8) Italy; and (9) 

 near Hudson's Bay. It is recommended that the 

 method be that employed at Williams Bay, Wis., 

 in 1915-16, and that the experiments extend over 

 a period of one year. 



The reason for the recommendation that the ex- 

 periments be carried out both inland and near the 

 coast is that it is desired to determine and to elim- 

 inate the efforts of the ocean tides on the general 

 tidal deformations of the earth. The reason for 

 the recommendation that two stations be in the 

 southern hemisphere, is that it is desired to deter- 

 mine whether or not the two hemispheres of the 

 earth differ in their deep interiors aa they do in 

 their surface features. 



2. Results to ie Obtained. — The proposed ex- 



periments will determine the magnitudes of the 

 tidal deformations of the earth of various periods 

 from the semi-daily to the semi-annual within 

 about one tenth of one per cent., and will determine 

 the phases of the principal tides within one minute 

 of time. These results are of an order of accuracy 

 that leaves nothing to be desired. It is poissible 

 to determine from the magnitudes of the earth 

 tides the stiffness of the earth, considered as a 

 whole, with a corresponding degree of accuracy; 

 and to determine from the phase relations of t" 

 tides to the tide-raising forces whether the earth 

 yields as a viscous or as an elastic body, or to 

 what extent it is elastico-viscous, to use Sir 

 George Darwin's term. 



The foregoing results are deemed important for 

 the following reasons: 



(a) They give reliable information about 

 hitherto almost unknown properties of the earth. 



(6) They throw some light on the effects of 

 enormous pressures on the properties of matter. 



(c) They enable us to determine accurately the 

 present rate of tidal evolution. 



(d) They give the geologist a secure basis for 

 theories regarding earth deformations, at least at 

 the present time. 



(e) They have important relations to doctrine 

 of isostasy. 



(/) They form a necessary preliminary to a 

 complete treatment of ocean tides. 



(g) They are valuable in connection with theo- 

 ries respecting the origin of the earth. 



3. Cost of Experiments. — The cost of the instal- 

 lation of the necessary apparatus for the experi- 

 ments will be about two thousand dollars for each 

 station, and the expenses of maintenance for a 

 year and the securing and measuring of the records 

 will be about four thousand dollars additional. 

 That is, the total cost of each station will be about 

 six thousand dollars. 



4. Type of Apparatus and Personnel. — It is 

 recommended that all stations use apparatus of 

 identical type, namely, that employed at Williams 

 Bay, Wis., in the second series of experiments of 

 1915-16. This will insure that all the results will 

 be comparable, at least so far as they depend upon 

 the apparatus. 



It is recommended that the experiments be car- 

 ried out simultaneously, or at least that they 

 largely overlap in time, so that any general 

 seismic or other possible disturbances may not lead 

 to erroneous conclusions respecting differences in 

 the properties of the earth in widely different 

 parts. 



