( 50 ) 
some of the modifications of lime: vegetable mould 
is black and friable, but nut exclusively so: for 
schistous and carbonaceous earths have the same 
properties. 
It is here, then, that chemistry offers herself to 
obviate difficulties, and remove doubts ; but neither 
the apparatus nor process of this science, are with- 
in the reach of all who are interested in the enquiry, 
and we accordingly subjein a method, less compre- 
hensive, but more simple and sufficiently exact, for 
agricultural purposes, and which calls only for two 
vases, a pair of scales, clean water and a little sul- 
phuric acid. 
“ Ist. Take a small quantity of earth from differ- 
ent parts of the field, the soil of which you wish to 
ascertain, mix them well together and weigh them ; 
put them in an oven, heated for baking bread, and 
after they are dried, weigh them again; the differ- 
ence will show the absorbent power of the earth. 
When the loss of weight in 400 grains, amounts to 
50, this power is great, and indicates the presence 
of much animal or vegetable matter; but when it 
does not exceed twenty, the absorbent power is 
small, and the vegetable matter deficient.(1) 
2d. Put the dried mass into a vase with one fourth 
of its own weight of clear water ; mix them well to- 
gether; pour off the dirty water into a second vase, 
and pour on as much clean water as before ; stir 
the contents, and continue this process until the 
water poured off is as clear as that poured on the 
+ 
(1) See Davy’s elements, a 
