544 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



Yalue of Lime in Poor Sandy Soils. 



" My filtration experiments point out the reason why marl 

 or lime is particularly valuable on poor sands. 



" In passing a solution of sulphate of potash through a 

 poor sandy soil, I found a weighable quantity of sulphate of 

 ammonia in the filtrate, which was not the case when the 

 same solution was passed through a marly soil. The power 

 of soils to retain ammonia is generally assumed to be greater 

 than their power of retaining potash. Here, however, an in- 

 stance is presented to us in which a salt of potash, by acting 

 on the ammoniacal combination in a soil, overcomes the sup- 

 posed suj^erior affinity for potash. Contrary to all expecta- 

 tion, ammonia, in combination with sulphuric acid evident- 

 ly supplied by sulphate of potash, passed into the solution, 

 while potash took its place and Avas retained in the soil. 

 The sterile land used in this experiment hardly contained 

 any lime ; while the marly soil, it need hardly be said, con- 

 tained it in large proportion. Lime acts beneficially on sandy 

 soils, not merely in a direct manner, by supplying a deficient 

 element of nutrition, but also because it preserves in the soil 

 the more valuable fertilizing matters which, like salts of 

 potash or ammonia, rapidly filter through sandy soils, un- 

 less a sufficient quantity of marl or lime has been previ- 

 ously applied to the land. By these means the bases of 

 the more valuable saline constituents of rotten dun 2; or of 

 guano are retained in the land, while acids filter through it 

 in combination with lime a constituent which is, compara- 

 tively speaking, inexpensive" {Jour. Ag. Soc. xiv., 2, 1878, 

 pp. 812,813). 



FURTHER CONCERNING CHEMISTRY OF SOILS. 



Carbonic Acid in Soils. 



Ebermeyer has been investigating the question of the car- 

 bonic anhydride in the air and soil of forests as compared 

 with free air and soil of open lands. The air was tested in a 

 wood of fir and beech, in open uncultivated soil, in a garden, 

 and in a meadow. Samples of air from above and below the 

 surface of the soil were taken three or four times a month, 

 from January to August. The results show that (1) the 



