1919] SOILS FERTILIZERS. 21 



benzine. The possible nature of the combined water, whether Chemical or 

 physical, is discussed. 



A real relationship was found to exist between the combined water and the 

 heat of wetting of soils, both factors tending to vary in the same order in most 

 of the soils examined. The heat produced ranged from <> calories for quartz 

 sand to 10.8 calories for Norfolk sand, 402.3 calories tor black day loam, and 

 1,109.25 calories lor peat for the 50 gm. of material used. The corresponding per- 

 centage of water that failed |o freeze in the respective suhstances amounted to 0, 

 L59, 13.85, and 70 per cent. "This comparatively tremendous amount of beat 

 represents energy expenditure on the part of one or both of the reacting mate- 

 rials. Evidences are deduced, however, which prove that all this energy expendi- 

 ture is at the expense of the water only and not at all at the expense of the soil, 

 [and] ... is the result of the water undergoing a transformation from its 

 liquid strrte of aggregation to a solid state of aggregation. This transformation 

 is caused or brought about by the chemical affinity or capillary affinity or both 

 that the soils have for water. The total heat of wetting is due partly to the 

 latent heat of water, partly to the affinity or attraction that the soils have for 

 water, and partly to the condition of the solid to which the water is trans- 

 formed. 



"In attempting to ascertain the exact nature of this solid water by deter- 

 mining the heat of wetting of soils and various artificial materials in water and 

 ligroin, it was found that with the exception of silica, lampblack, and triealcium 

 phosphate the heat of wetting of the solid materials in Ligroiu was either 

 entirely absent or comparatively very small. If to the solid materials was added 

 water while they were still immersed in the ligroin, heat was evolved. This 

 evolution of heat took place in all the agricultural soils except in the peat and 

 in all of artificial materials except in the quartz saud, lampblack, and barium 

 sulphate. The rapidity and magnitude of this heat evolution were almost the 

 same as in water alone, or as if the ligroin were not present at all. In water 

 alone, all the solid materials except lampblack gave more heat of wetting than 

 in ligroin alone. Lampblack, however, gave more heat of wetting in ligroin 

 than in water. 



"The difference in the heat of wetting of the various solid materials in the 

 different liquids indicates that the attraction or affinity of the different solid 

 materials for the different liquids is specific or selective. This specific or 

 selective attraction or affinity of the solid materials for different liquids is 

 not due entirely to the magnitude of the surface of the solid materials, but prin- 

 cipally to the chemical nature of the materials. The heat of wetting of mate- 

 rials by the addition of water when they are still immersed in ligroin indicates 

 that the specific or selective attraction or affinity of the solid materials for 

 water is not destroyed or satisfied by the substitution or presence of ligroin ; and 

 that this attraction or affinity of the solid materials for water will go through 

 a solid film or continuous membrane of ligroin to reach the water and thus 

 satisfy itself. The distance to which this force will be felt, even through an 

 intervening solid film or continuous membrane of another liquid, is considerable. 



"It appears to hold generally true that when a solid material is immersed in 

 a liquid for which it has only a small attraction or affinity and then a second 

 liquid is added for which the solid material has a great attraction or affinity, 

 the second liquid will be attracted by the solid material with as much force or 

 manifestation of heat as though the first liquid were not present at all. The 

 converse of this is not true. The remarkable phenomenon of the attraction or 

 affinity of a solid material being exerted for a liquid through an enveloping 

 solid or highly compressed film of another liquid throws an abundance of light 



