38 4 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



posed either by washing until all sulphuric acid was removed, 

 nor by heating to 210 Fahr. Eichhorn {Jahresh. f. agricid- 

 tur. Chimie, 1859-60, 16) has already shown that silicates, 

 which are decomposed by hydrochloric acid as chabazite, ab- 

 sorb ammonia from its salts. Magnesia acted more ener- 

 o-etically than any other agent, seven times more alkali and 

 three times more silica being dissolved than with water 

 alone. Its somewhat less action in combination with car- 

 bonic acid was probably due to the crystallizing of bicarbon- 

 ate oh the sides of the vessel. 



Sodium nitrate dissolved about double the quantity of pot- 

 ash that water did, but its action was less than that of so- 

 dium chloride. These comparative results are in unison with 

 those of Dietrich on basalt. 21 ^,Jfa?/, 1872, 386. 



IMPORTANCE OF SILEX IN THE SOIL. 



Silica oives hardness and stiffness to the straw and leaves 

 of cereal grain. When wheat or rye is sown where a brush- 

 heap or pile of logs has been burned to ashes, the straw will 

 be unusually stiff, and the leaves much harsher than other 

 straw growing in the vicinity, but away from the. area of 

 the burning. The potash of the ashes and the silica found in 

 the soil are taken up by the growing plants, and form a coat- 

 ing of liquid glass, which is spread evenly over the straw 

 and leaves of the growing grain, as a metallic coat of arms 

 was used in old times to cover the body of a soldier. When 

 the srrowino: straw of wheat is inclosed in a thin tube of elas- 

 tic glass, the innumerable spores, which frequently fill the 

 entire atmosphere like flakes of snow, and which produce 

 rust, do not find a congenial place for their lodgment and 

 complete development. But when the plants do not have ac- 

 cess to a generous supply of silicate and potash, the stems are 

 so limber that they are easily prostrated by driving storms, 

 so that the ears of grain will be developed only in part. 

 When silica is available only in small quantities, the spores 

 from which fungi spring adhere to the leaves and stems, 

 where they find a suitable spot for their development, and 

 thus the productiveness of the plant is seriously impaired. 

 The practical value of silica is further perceived in the yield 

 of excellent fruit. If the soil near an apple or a pear tree, 

 that has hitherto borne knotty and rusty fruit, receive a lib- 



