BUREAU OF SOILS. 291 



of the soils about the great centers of civilization whose populations 

 have lived in large measure on the products of the soil of their imme- 

 diate vicinities. 



Accurate data relating to the soils around London, Paris, Madrid, 

 Rome, Athens. Constantinople, in Roumania and India, and about 

 Pekin and Tokyo, such as are contained in our own detailed soil sur- 

 veys, including a study of soil formations, correlating them as nearly 

 as possible Avith our own soil types, information as to the length of 

 time such lands have been under cultivation, with records of yield 

 and laboratory analyses of samples — these to be compared with simi- 

 lar studies in South America and British North' America, where the 

 soils have never been used for agricultural purposes — would be a 

 decided contribution to our scientific knowledge of soils and would 

 ultimately be of unquestionable value to practical agriculture. 



CHEMICAL INVESTIGATIONS. 



During tlie year the laboratory of soil chemical investigations has 

 <lone the usual large amount of routine work. Many complete or 

 partial analyses of soils have been made for the Soil Survey, for other 

 bureaus of tlie Department of Agriculture, and for other departments 

 of the (Government, as well as for hundreds of farmers, gardeners, 

 and city and suburban dwellers. Tliere have also been the usual 

 routine investigations of the effect of lime and other fertilizers on 

 the soil. 



There are two lines of investigation, however, that stand out 

 prominently as fundamental advances in the science of soils, and 

 Avhich it is believed if carried out with a larger force will have very 

 important results on the practice of agriculture. Both of these lines 

 have been under investigation for some 3'ears, but have onl}^ during 

 the last year taken that definiteness that permits of their being an- 

 nounced in this public way. 



Chemists have long been dissatisfied with the interjiretation of the 

 chemical analyses of soils, as the results have l)een of only relative 

 value and little was known of the actual constitution of the ma- 

 terials which were found. 



The Bureau of Soils has at last been able to treat soils in ton lots 

 and to determine the actual crystalline form of many of the soil 

 constituents. It has been found that the salts occurring in the soil 

 solution are much more complex than had been realized, and that 

 the salts in the soil mixture are of the same general type as those 

 in the Stassfurt deposits of Cermany and in the beds of former 

 inland seas and lakes that have evaporated and left their salts as 

 deposits. This might have been foreseen, for the soil is the original 

 source of these deposits that have been carried by the rivers into 

 the sea and finally left by evaporation after the water supply has 

 been cut (jff. Still it is striking to find in our ordinary soils such 

 well-known minerals as kainit, carnallite, kieserite, and sylvite, which 

 commercially are knoAvn onl}' in connection Avith such deposits as 

 occur at Stassfurt. The soil, therefore, appeal's to be a miniature 

 Stassfurt deposit. 



Suflicient progress has been made to show that these complex 

 mineral salts differ in some respects in our different soil types. 

 What the significance of this is in ]iractical agriculture has not yet 



