io8 NATURAL SCIENCE. Feb., 



When the Geological Section has done its work, it is succeeded 

 by the Agronomical, whose province it is to construct maps showing 

 the various soils, to examine those soils with the view of discovering 

 means by which their fertility may be preserved or improved, and, 

 more especially, to survey those portions of the Empire that are not 

 yet under cultivation, to see how far they are capable of it, and to 

 investigate the quality, abundance and accessibility of the various 

 mineral manures. Although not unknown in other European 

 countries more advanced than ourselves, and although the British 

 government geologists have of late begun to publish maps showing 

 the surface geology, still we have but a small idea of a survey so 

 thoroughly scientific in its working, so eminently practical in its 

 application and so completely fulfilling those promises that were held 

 out to the public when our own Geological Survey and Museum of 

 Practical Geology were first started. For these reasons, an account 

 of the Japanese Agronomical Survey, more detailed than has 

 been given of the other Sections, may be of value as well as 

 interest. 



It is recognised that the nature of the solid rocks of any country 

 has directly but a slight effect on its agricultural conditions ; and this 

 is especially the case in districts where there is a large amount of 

 alluvium or of drift. On the contrary it is the soils, that is the 

 weathered products of the solid rocks, often far removed from the 

 original rock, that have most influence on the fertility of the land. 

 The main object of the agronomical survey in its relation to geology 

 is, therefore, to divide the soils derived from the different kinds of 

 rocks into as many types as possible, and to judge the relative capa- 

 bilities of those soils for cultivation. Hence the survey is not confined 

 to the cultivated land, but is extended to regions that appear 

 capable of cultivation and also to the forest ground. 



First comes the field-work. On the maps already prepared by 

 the Geological Section, on a scale of 1:500,000, the surveyor sketches 

 the distribution of the various soils. He notes the relations of the 

 soils to their mother rocks at different stages of weathering, and 

 collects typical samples of both. The following notes are also made : — 

 the mode of origin and the petrographical character of the soil ; the 

 nature of the subsoil, illustrated by sections and borings, to a depth, if 

 possible, of three metres ; the height of the land above sea-level ; the 

 configuration of the land; the underground water level; local climatic 

 conditions; the registered value of the land; the conditions, methods 

 and results of the farming actually carried on, with particulars as to 

 rotation of crops, manures and similar agricultural details. 



The samples of soils collected are next investigated in the 

 laboratory, to find their mechanical composition, chemical constitu- 

 tion, physical properties and absorptive power. To determine its 

 mechanical composition, each sample is quantitatively separated 

 into thirteen parts according to the size of the grains, thus : — 



