524 EXPERIMENT STATION RECORD. 



" (9) A plea for the rational statement of analytical data, inasmuch as it is the 

 ions which are determined and not the salts. Fnrthermore, it is the ions with which 

 we are generally concerned in the study of any particular problem. 



"(10) A field method for the (>stimation of sulphates, chlorids, and carbonates, 

 involving 3 titrations whicli may all be made on the same sample in one vessel, 

 Its use in retionnoissance work is described. 



"(11) A rapid method for the estimation of sodium carbonate in the presence of 

 the bicarljonate, <lepending on the conversion of the alkaline carbonate to the neutral 

 acid carbonate, with the formation of a neutral suljjhate by the addition of acid 

 potassium sulphate. The use of the method in the lal)oratory and in the field is 

 described, and its probable availability for technical work is suggested. The objec- 

 tions to the use of sulphuric acid in determining 'alkalinity' are made evident. 



" (12) Observations on the hydrolysis of so<lium carbonate and sodium silicate and 

 the inversion of sodium bicarl)onate and sodium bisilicate to the normal salts are 

 described l)riefly. 



" (13) A discussion on the formation of hardpan and similar deposits, in which it 

 is pointed out that the hydrolysis of the salts of weak mineral acids and subsequent 

 desiccation and deposition of the solution products must be taken into account in any 

 hypothesis as to their genesis. 



"(14) An explanation of the solution and hydrolysis of certain minerals and the 

 consequent alkalinity they display. 



" (15) Suggestions for the study of the functions of fertilizers, in which the impor- 

 tance of considering the solution phenomena which their j^resence may effect in the 

 ground waters is made evident. 



" (16) Some observations on selective absorption and other physico-chemical phe- 

 nomena which are incidental to a complete study of the properties of a soil." 



A paper on methods of mechanical analysis as applied to alkali soils 

 discusses the dis in teg-ration of such soils during the progi'css of analysis 

 due to the solvent action of the water used in making the mechanical 

 separation, and describes apparatus and methods applicable to such 

 soils, attention lieing called especiall}' to the advantages of the cen- 

 trifugal method for this purpose. The treatment after ignition of the 

 mechanical separations with carbon dioxid, according to Hilgard and 

 Jafla, to convert the oxids of the alkaline earths into car])onates, is 

 recommended, and the application of the electrical method (E. S. B. , 

 11, p. 325) to the determination of the water-soluble content of soils in 

 connection with their mechanical analysis is explained. 



The conclusions from the investigations on the influence of sodium 

 clilorid, sulphate, and carbonate upon the rate of evaporation of water 

 from soils are summarized as follows: 



"(1) Salts influence the evai)oration of water from the surface of a soil by changing 

 the surface tension, the viscosity and the vapor pressure of the system, and the ]iliysical 

 character of the soil, particularly at the surface. 



" (2) The surface tension and viscosity influence the rate of evaporation only through 

 the modification of the rate of capillary movement. Both surface tension and vis- 

 cosity increase with increase in concentration. An increase in surface tension increases 

 the rate of capillary movement, while increase in viscosity diminishes it. These two 

 factors consequently oppose one another. 



"(3) The rate of capillary movement within a soil is of secondary importance to 

 the physical character of the surface, as modified by the })resence of crystallized salts. 



"(4) The relative rate of evai)oration from a soil moistened with piu"e water and 



