PROCEEDINGS OF THE CHEMICAL DEPARTMENT. 103 



until it was thoroughly air dried, and the clods were broken down 

 with a piece of wood. The whole was then passed through a 

 sieve of eight holes to the inch, and the portion remaining on it 

 was set down as stones or gravel ; while that which passed through 

 was the soil, and was submitted to chemical analysis, after having 

 been reduced to fine powder in an agate mortar. 



A quautity of the pulverised soil was weighed off, and digested 

 for some hours at a heat approaching the boiling-point, with 

 dilute acetic acid, containing 7'5 per cent of the real acid. The 

 insoluble matter was separated by filtration, and carefully washed 

 with water. The solution was divided into five portions, of 

 which one was used for the determination of iron, alumina, lime, 

 and magnesia. The iron was determined by permanganate, and 

 the other constituents in the usual manner. A second portion was 

 used for alkalies, and the other three served for sulphuric acid, phos- 

 phoric acid, and chlorine, or such of them as happened to be present. 



Another portion of the soil was treated with hydrochloric acid, 

 and the solution being filtered, the washed residue was weighed. 

 The sohition was then evaporated for the separation of soluble 

 silica, and the filtered fluid divided into portions for the estima- 

 tion of the different constituents, which were determined by the 

 ordinary processes. 



A third portion was used for the determination of carbonic acid. 



The matter insoluble in acids was fused with a mixture of 

 carbonates of potash and soda, the solution evaporated for 

 separation of silica, and iron, alumina, lime, and magnesia 

 determined in the fluid. The sum of these constituents always 

 amounted to within a fraction of a per cent, of the quantity used, 

 and showed that alkalies were either entirely absent in the insoluble 

 part, or were present in it in so small a quantity as to render it 

 unnecessary to make separate estimations of potash and soda.* 



Hygrometric moisture, organic matter, and nitrogen were then 

 determined in separate portions of the soil. The results of all 

 these determinations having been calculated in one-hundredth 

 parts, the quantities obtained from the acetic solution were 

 deducted from those of the hydrochloric solution, and the 

 difference gave the amount of each constituent soluble in hydro- 

 chloric acid, and insoluble in acetic acid. 



The numbers so obtained give as exact an idea of the chemical 

 composition of those soils as it is well possible to have in the 

 present state of our knowledge ; but, in order to complete the 

 investigation, a mechanical analysis was also made by Schultze's 



* It is interesting to notice the contrast in this respect between these soils 

 and the wheat soils analysed for this Society some years since. Some of the 

 latter contained a large quantity of alkalies in the insoluble portion. It must 

 be remembered that the soils in question were of very high quality, and selected 

 as typical wheat soils of great fertility. 



N 



