no 



NATURAL SCIENCE. 



Feb., 



To answer well the practical questions on manuring, the absorp- 

 tion of phosphoric acid and nitrogen in the soil must be examined. 

 This is effected in the ordinary way, by means of the "bottle method,' 

 using as absorbents monocalcium phosphate and sal ammoniac. 

 However the use of the above absorbents has recently been found 

 unsatisfactory, and at present ammonium phosphate is employed, 

 although its exact standard has not yet been absolutely determined. 



The maps published by the Agronomical Section are based upon 

 those already prepared by the topographers, on a scale of i : 100,000. 



Instead, however, of being separated into squares, as are the ordinary 

 geological maps, they follow the lines of provincial and prefectural boun- 

 daries. On these maps the geological formations are represented by the 

 usual colours, while the characters of the soils, classified according to 

 physical conditions, are shown by inchned lines of different colours 

 or crowded spots of various sizes in darker colours. Sections of the 

 subsoil are delineated on one side of the map, and the spots where 

 they were observed are denoted on the map by corresponding 

 Roman numerals. In the summer of last year 27 prefectures had been 

 surveyed and the maps of 12 published, as shown in the above figure. 



