618 
On the Analysis of Soils. 
lime will remain upon it, to be dried, ignited, and weighed. Five parts 
of it correspond to four of phosphate. The iron is obtained by precipi- 
tation with water of ammonia, filtration, and ignition. 
The first filtered liquor, with excess of ammonia, contains the lime of the 
carbonate, and the magnesia. The former is separated by a solution of 
oxalate of ammonia, with digestion in a gentle warmth for a few hours, 
filtration, and very gentle ignition of the washed dry powder, when the 
pure carbonate of lime is obtained. The magnesia, existing in the 
filtered liquor as an ammonia-muriate, may be obtained by precipita- 
tion with soda, or phosphate of soda, as already described. 
For some refractory soils, in which the alumina exists as a double or 
triple silicate, it becomes necessary to fuse 50 grains of the sample, in 
fine powder, mixed with four times its weight of dry carbonate of soda, 
the mixture being put into a platinum crucible, and into a cavity in its 
centre, 50 grains of hydrate of potash being laid. 
The crucible being slowly raised to a red-white heat, affords a fused 
liquid quite homogeneous, of a gray or brown colour, according to the 
metals present in it. Manganese gives a purple lint ; and iron a red- 
dish brown. The fused matter should be poured out into a shallow 
platinum basin ; and, whenever it cools, it should be pulverized, dissolved 
in dilute muriatic acid, the solution evaporated to dryness, the dry mass 
again digested in hot water, acidulated with muriatic acid, and the 
whole throw-n upon a filter. Pure silica will remain on the filter, to be 
washed, dried, ignited, and weighed. 
The filtered liquor contains the remaining constituents of the soil, and 
is to be treated as already described. 
Besides these systematic investigations, researches may be made for 
certain peculiar substances, and especially the neutro-saline constituents. 
In this view 100 grains of the soil maybe triturated with 20 times their 
weight of distilled water, placed in a beaker, till the clayey matter sub- 
sides, and the clear portion then be decanted into a filter. A little of 
the filtered liquor should be tested with nitrate of barytes, and also witli 
oxalate of ammonia; and if each portion yields a precipitate, they show 
the presence of sulphate of lime ; and the following steps ought to be 
taken to eliminate it entirely : 200 grains of the soil should be triturated 
with a quart of distilled water, holding 50 grains of sal-ammoniac, in sola 
tion. The mixture should be allowed to clarify itself by subsidence, 
when the supernatant clear liquor should be filtered, and evaporated down 
to 2 ounce measures, and then mixed with that bulk of strong whiskey 
(11 ]ier cent, overproof). The whole sulphate of lime will be now 
separated from the fluid, and after being drained on a filter, may be 
dried, ignited, and weighed. 
For determining the alkaline salts, the water filtered from the 100 
grains of the soil should be evaporated down to one-fifth of its bulk, and 
then treated — 1st, with nitrate of barytes for the sulphates; 2n(l, with 
nitrate of silver for the muriates ; 3rd, with oxalate of ammonia, lor the 
nitrate or muriate of lime (])rovided no sulphate of lime is indicated by 
the first test) ; 4th, with litnms paper, for alkaline or acid reaction ; 5th, 
with soda-chkiride of platinum for potash salts, which arc very valuable 
for the vigorous growth of many plants. 
The portion of soil tested for potash salts should, before bcuig digested 
