174 REPORTS ON INVESTIGATIONS AND PROJECTS. 



In addition to the above investigation, two analyses were made of the 

 well-known syenite of the Plauenscher Grund. These differ widely in some 

 important respects from the earlier ones, and were published in the Ameri- 

 can Journal of Science (v. xxii, 1906, p. 129), with a description of the type 

 and discussion of its systematic position. Short papers are also being pre- 

 pared on some rock types from Santorini and Monte Vulture, analyses of 

 which have been made. There is also being written an extended discussion 

 of the chemical conditions controlling the formation of leucite in igneous rocks, 

 which is a theoretical extension of observations made in connection with the 

 study of the leucitic rocks of central Italy. 



GEOPHYSICAL RESEARCH. 



Adams, Frank D», McGill University, Montreal, Canada. Grant No. 335. 

 Investigations on the flow of rocks. (For previous reports see Year Book 

 No. 2, p. XXXIV; Year Book No. 3, p. 119, and Year Book No. 4, 

 pp. 230-231.) $1,500- 



The investigation into the elastic constants of rocks, which was undertaken 

 by Professor Adams in conjunction with Dr. E. G. Coker, was completed last 

 October and the results have appeared in Publication No. 46 of the Carnegie 

 Institution of Washington, entitled "An investigation into the elastic con- 

 stants of rocks, more especially with reference to cubic compressibility." 

 An abstract of this paper was also published in the American Journal of 

 Science for August, 1906. 



The attempt to measure the cubic compressibility of rocks by another 

 independent method — that proposed by Messrs. Richards and Stull — was 

 also continued during the past year, and while the experimental difl&culties 

 have not as yet been entirely overcome, it is expected that satisfactory 

 measurements will be obtained by its use during the coming year. 



The experimental work which has been carried on during the past year 

 consisted chiefly, however, of an elaborate series of measurements of the 

 internal friction developed in rocks when these were subjected to very slow 

 deformation under varying conditions of differential pressure. The investi- 

 gation was made to cover nine typical rocks, namely : 



Alabaster, Castelino, Italy. Sandstone, Cleveland, Ohio. 



Soapstone, Virginia. Slate, New Richmond, Canada. 



White Marble, Carrara, Italy. Diabase, Sudbury, Canada. 



Black Marble, Belgium. Granite, Baveno, Italy. 

 White Dolomite, Cockeysville, Maryland. 



Comparative measurements were made with the metals copper and lead. 

 Sixty-six complete determinations of internal friction have been made up to 

 the present date, and the investigation, which will be completed during the 

 coming year, will furnish, it is believed, valuable data bearing upon a 

 number of problems in geophysics. 



