G18 STATE BOARD OF AGRICULTURE. 



power. It has been abuiulaiilly proved, for exaini»lo, that when clay is 

 heated its absorbiive power for water is greatly diniini.shed. 



This hypothesis, therefore, wonld seem io explain very well the di- 

 minution of I he depression of the free'/ing point of the agricultural 

 soils at low moisture content Avith repeated freezings. It would seem 

 also to suggest that the artificial substances, such as the quartz sand, 

 burned silicic acid, and kaolin, either do not contain colloidal material, 

 or if they do, it is not coagulable. 



At the high moisture content coagulali(ni of the colloids of the agri- 

 cultural soils should also take place, but since the amount of water 

 present is high, and the solution is relatively very dilute, the amount of 

 water that i,s released upon coagulation is too small to make any notice- 

 able effect upon the depression. 



In late years a great amount of work has been done upon the effect 

 of steam heat on the solubility of soil constituents. Especially impor- 

 tant and valuable are the investigations of Russel and Hutcheson, (15), 

 and Lyon and Bizzel, (10), upon the subject. These investigators, as 

 well as others subsequently, found that in general, steam heat increased 

 the ammonia content as well as the Avater-soluble inorganic matter. 



In order to show the applicability of the freezing point method on 

 this subject and also to ascertain to what degree the steam heat in- 

 creases the concentration of the solution, the lowering of the freezing 

 point of a few types of soil steam heated, Avas determined. The gen- 

 eral procedure consisted of taking soils from the field, bringing them 

 up to a high moisture content, and then dividing each soil into Iavo 

 parts, one part Avas used as a check and the other part w^as steam 

 heated in an autoclave for about 3 hours at a pressure of 15 atmos- 

 pheres. After steaming, the moisture content was brought up to the 

 original and the lowering of the freezing point Avas determined. The 

 folloAving table contains the depression of the freezing point of the 

 unsteamed and steamed portions of each soil. Only a very limited 

 number of soil types Avas emploAed because it Avas desired to show 

 mainly the applicability of the method on the subject. 



Table 0. Effect of Steam Heat on the Lowering of the Freezing Point of Soils. 



Name of Soil. 



Lowering of 



the Freezing 



Point. 



Sandy loam unsteamed . 

 Sandy loam steamed . . . 



Clay unsteamed 



Clay steamed 



Clyde loam unsteamed . 

 Clyde loam steamed . . . 



Peat unsteamed 



Peat steamed 



.020 

 .035 

 .030 

 .045 

 .040 

 .115 

 .015 

 .065 



It Avill be at once seen tliat steam heat increased the lowering of the 

 freezing, and consequently the concentration, in every soil, but the 



(16) Jour. Agr. Sei. 2, 411, 1908. 



('6) New York Cornell Sta., Bui. 275,'1910. 



