200 CARNEGIE INSTITUTION 



INVESTIGATION OF METAMORPHIC ROCKS. 



I. Detennination of heat co?iductivity in solid rocks and crystals. 



II. Porosity of rocks. 



(a) With regard to the transmission and circulation of 



water. 



(b) With regard to the transmission of gases. 



III. Solubility of rock-making minerals in water. 



(a) At various temperatures. 



(b) At various pressures. 



IV. Solubility of rock-making minerals hi vapors. 



(a) At various temperatures. 



(b) At various pressures. 



(c) Also in mixtures of water and gases of various kinds, 



dilute acids. 



V. Solution and recrystallization. 



Chemical reactions at various temperatures and pressures. 

 Examples : Wollasto?iite converted to calcite. 

 Calcite converted to wollastonite. 



VI. Physical changes accompa?iyhig hydration and dehydration. 



VII. Grozvth of large crystals at the expense of small o?ies under static 

 conditions. 

 The development of large, pseudoporphyritic crystals, ottre- 

 lite, staurolite, garnet, etc., in certain schists. 



VIII. Solution and recrystallization of strained crystals of rock-making 

 minerals, and of other salts. 



IX. Changes resulting from differential stresses. 



i. Determination of the relation between the rate of de- 

 formation and the strength of the deformed rock. 



2. Relation between the amount of deformation and the 



degree of pressure producing it. 



3. The resistance offered by rocks to deformation. 



4. The deformation of hot rocks in the presence of water. 



5. The relative degrees of deformation experienced by 



given rocks at different temperatures and with 

 different content of water, for different pressures, 

 with limestone, marble, sandstone, granite, etc. 



