2g8 TABLE 276.— COMPRESSIBILITY OF CRYSTALS (concluded) 



Part 2. — Elastic constants of rocks at ordinary pressure and temperature. 



E = Young's modulus, in dynes cm" 1 

 G = Modulus of rigidity, in dynes cm" 2 

 a = Poisson's ratio, dimensionless 



The density is given, when known, in parentheses in the first column. 



E 

 Rock dynes cm- 2 



Granite, coarse gray, 



Quincy, Mass 4.64X10 1 ' 



Quincy, Mass. from 100 ft 

 depth (2.67) 3.48 



Basalt, Ostritz 11.15 



Dl3Dd\SC 



Westfield, Mass. (2.95) 8.00* 



Marble 



Proctor, Vt. (2.71) 3.43 



4.60 

 4.95* 

 Limestone 



Knoxville, Tenn 6.21 



Montreal 6.35 



Dolomite, Pennsylvania (2.83) 7.10* 



Sandstone 



Quartzitic, Penna. (2.66) 6.36 



Feldspathic, Ohio 1-58 



Slate, Pennsylvania, 1 1 to cleavage 



plane 11.29* 



Shale (2.63) 4.4 dry 



1.9 wet 



Schist, Mica, Japan 1-6 



Tuff, Japan 3-3.6 



Ice (.917) -5°C 917* 



* Dynamical measurements. 



G 



dynes cm -2 



(1.92) X 10" 



2.17 



(2.48) 

 (2.50) 



3.23 



( -61) 

 4.65 



.336 



.215 



.141 

 .190 



.251 

 .252 



.115 

 .290 



(.365) 



Stress or 



stress 



range 



kg cm- 2 



70-600 

 11.2 



100-900 



11.2 

 56 



70-600 

 70-600 



11.2 

 70-600 



200 



TABLE 277. 



-RELATIVE VOLUME OF QUARTZ CRYSTALS AND SIX GLASSES 

 FOR DIFFERENT PRESSURES" 5 



Quartz 



65 Bridgman, P. W., Proc. Amer. Acad. Arts and Sci., vol. 76, p. 68, 1948. 



* Glass A is a potash lead silicate of very high lead content. t Glass C is a soda potash lime 



silicate. J Glass D is a lead zinc borosilicate. 



SMITHSONIAN PHYSICAL TABLES 



