EXPERIMENT STATION BULLETINS. 293 



LIST OF MINERALS EMPLOYED AND THEIR FORMULAE 



Apatite ' (CaF) Ca4(P04)3 



Amphibole (AlFe).03, (Mg, Ca, Fe)0, SiO^ 



Apophyllite H7KCa4(Si03)8+43/^ H2O 



Calcite CaCOa 



Chrysolite (olivine) (Mg, Fe)2Si04 



Epidote Ca2([Al, FeOH]) (ALFe^ (Si04) 3 



Gypsum CaS04 + 2HJJ 



Syenite, 2 varieties FeOa 



Kaolinite H4Al2Si209 



Limonite 2Fe2033H20 



Oligoclase 3(NaAlSi308) + (Ca, Al2Si208) 



Orthoclase K Al Si03 Os 



Prochlorite H40(Fe, Mg)23Ali4Si,309o 



Pyroxene Magnesium-iron-ealeium-silicate 



Quartz (milky var.) Si02 



Serpentine H4Mg3Si209 



Siderite FeCOs 



Stilbite H4(Na2Ca) A^SisOis + 4 H2O 



Talc H2 Mg3 Si40i2 



Zircon Z2Si04 



AMOUNT OF READILY SOLUBLE MATERIAL IN ROCKS AND MINERALS 



Before the results on the rate and extent of solubility on long standing 

 are presented, it may be advantageous and of interest to consider first the 

 amount of readily soluble material in the various rocks and minerals inves- 

 tigated. These data are shown in table 1. They were obtained by mixing 

 the powder with definite amounts of distilled water and determining the 

 freezing point depression immediately. Two different moisture contents 

 were employed, low (20%) and high (75%), but since the results at the 

 former moisture content are not complete, only those of the latter are here 

 presented. 



TABLE 1 



Amount of Readily Soluble Material in Rocks and Minerals at 75 per cent 

 of Moisture. Figures represent freezing point depression. 



Name of rocks and mineral 75 per cent moisture 



C° 



Banded biotite gneiss .015 



Banded granite 021 



Biotite granite 018 



Biotite granite 020 



Biotite granite 019 



Compact lithographic limestone 018 



Crumbled mica-schist 010 



Diabase 020 



Diorite 020 



Ferrugineous sandstone 050 



Ferrugineous sandstone 057 



Ferrugineous sandstone 045 



Ferrugineous sandstone 010 



Ferrugineous sandstone 010 



