292 STATE BOARD OF AGRICULTURE. 



pass a 100 mesh sieve. The solubiHty of this powder was then measured 

 in the leached and unleached condition in distilled water, treated with salt 

 solutions and then washed until all the free soluble salts were eliminated, 

 and in the presence of salt solutions. The moisture content in all cases 

 except one was 1 of solid to 0.75 of liquid. The temperature employed was 

 room temperature, a temperature of 53°C, and at a steam pressure of 26 

 pounds which is equivalent to a temperature of about 117°C. The materials 

 were contained in glass freezing point tubes of high quality. The freezing 

 point depression was determined immediately upon the powder coming 

 in contact with water or salt solution, once every day thereafter for the 

 first four or five days, and at various intervals thereafter for a long period, 

 in some cases for more than 100 days. 



Although the solubility of rocks and minerals has been studied from time 

 to time by quite a number of investigators (3) yet strangely to say the sub- 

 ject has not received the complete and comprehensive investigation that it 

 deserves. There is, therefore, much work yet to be done upon the problem 

 and a good deal more to be learned. Furthermore, the rate and extent of 

 solubility of rocks and minerals have never before been studied by the freez- 

 ing point method, which has proved highly appropriate and unique for this 

 purpose. 



LIST OF ROCKS AND MINERALS EMPLOYED 



Following is a list of rocks and minerals employed in the study of the rate 

 and extent of their solubility. These rocks and minerals came from three 

 different sources: (1) from the Ward's Natural Science Establishment, 

 Rochester, New York, (2) from the Geological Department of the Michigan 

 Agricultural College, and (3) from a collection gathered by the writer. 



LIST OF ROCKS EMPLOYED AND THEIR PREDOMINANT MINERALS 



Banded biotite gneiss quartz, feldspar, mica 



Banded granite hornblend, quartz, feldspar 



Biotite granite, 3 varieties feldspar, quartz, biotite 



Compact lithographic limestone 



Crumbled mica-schist mica, quartz, feldspar 



Diabase plagioclase feldspar, augite 



Diorite plagioclase feldspar, hornblend 



Ferrugineous sandstone, 5 varieties . . . 



Hornblend granite hornblend, quartz, feldspar 



Hornblend basalt hornblend, plagioclase, pyroxene 



Hornblend gabbro hornblend plagioclase, feldspar, lab- 



rodorite. 



Hydrohlic limestone 



Marble (dolomitic) 



Mica-schist mica, quartz, feldspar 



Pegmatite feldspar, quartz 



Peridotite olivine, augite 



Quartzite, 3 varieties quartz 



Scotch granite feldspar, hornblend, quartz 



Shale, 2 samples 



Siliceous dolomite 



Siliceous sandstone 



Hematite (micaceous) hornblend, feldspar 



