1894. 



NATURAL SCIENCE IN JAPAN. 



109 



A sample of soil is first passed through a sieve with meshes 4 mm. 

 in diameter, and the fine soil thus separated is mechanically analysed 

 by Schone's apparatus, by which the soil particles from 11 to 13 are 

 washed out one after another with the respective pressures of -2 mm., 

 2 mm. and 7 mm. velocity per second. The soil remaining in the 

 cylinder of the apparatus is then separated by a set of sieves which 

 have meshes with the respective diameters of 3, 2, i, -5 and -25 m m. 



For the chemical analysis a sample of soil is treated with 

 concentrated hydrochloric acid, having a specific gravity of i-2, by 

 which the available constituents of soil can be well detected. The 

 fine-earthy part of the soil is boiled in the acid for an hour and, after 

 passing through the usual operation, an extract is made from which 

 Alumina, the Iron oxides, Manganic oxide, Lime, Potash, Magnesia, 

 Soda, Phosphoric acid, Sulphuric acid and Silica (soluble in hydro- 

 chloric acid and sodium carbonate) are successively determined 

 Iron in the ferrous state is estimated by the "copper method" (Fesca, 

 Joimt. fur Landwirthsc haft, 1884, pp. 407-421) and, for a soil rich in 

 humus, Carbon and Nitrogen are estimated, and in some cases 

 Chlorine is determined. In order to examine the character of clay 

 and its contents in the soil, the insoluble residue left after treating 

 the soil with hydrochloric acid is fluxed with sulphuric acid, and 

 the quantities of Alumina and Silica contained in it are then 

 estimated. 



The systematic examination of the physical properties of soil is 

 fully described in Dr. Fesca's " Abhandlungen und Erlaiiterungen 

 zur agronomische Karte Provinz Kai," pp. 3-19. Briefly, the weight 

 and permeability have to be noticed. The volume- or absolute weight 

 and the specific gravity of the soil are estimated ; and as the volume- 

 weight of the soil varies directly as its porosity, the weight of each 

 sample of soil is thus ascertained either in a loose or a compact state. 

 The permeability of the soil to air and water is examined b}' 

 ascertaining the water capacity and air contents of the soil, and by 

 observing its imbibing and capillary powers during the process of 

 experimenting. 



