REVIEW. 
35 
weights, will be the specific gravity, and the less this is, the greater will be the 
capacity of the soil to take up and retain water. Muschenbroett thus found rich 
garden soil to be 1630 compared to 1000 of water, and Fabroni found a barren 
sand to be 2210 compared to 1000 of water.” 
“ Or fill a wide necked pint or quart bottle half full of water, and add the 
soil to be tried till the water rises to the brim. Then if the bottle can contain 
one pound of water, and gains half a pound additional when filled in this way, 
half with water and half with soil, the soil thus tried will be twice as heavy as 
water, and its specific gravity will be two. If it only gain a quarter of a pound, 
its specific gravity will only be one.” 
M. Giobert ascertained that a pound of fertile soil contained, of flinty sand, 
about 4400 grains, of clay, about 600 grains, of Lime about 400, besides 70 of 
water, and about 25 grains of inflammable materials, chiefly carbon. On a com 
parative trial of a barren soil, M. Giobert found that a pound weight contained 
about 3000 grains of flinty sand, about 600 grains of clay, about 400 grains of 
lime, and a little or no inflammable materials. M. Grisenthwaite directs an 
equal portion of two soils, perfectly dry, to be introduced into two tall glasses, 
in the midst of each of which a glass funnel has been previously placed. Fig. 3. 
The soils are to be put in so as to retain, as nearly as possible, their natural state 
when in the ground, and are consequently not to be too much pressed down. 
When this has been done, water is to be 
poured very gradually into each of the 
funnels, and it will rise up as it does in a 
piece of lump sugar, into the dry soil, as 
may be seen through the glass. The 
more rapidly the water is seen to rise, 
the better will be the texture of the soil. 
At page 53, when treating on the 
Principles of Manuring, we find the fol¬ 
lowing observations : “ As the chief food 
of plants consists of carbonic acid gas, and humic acid, mixed with water, it is 
clear that every sort of manure, whether it be simple or mixed with other sub¬ 
stances in the form of compost, must be tried and judged, in the first place, by 
the proportion of carbonic acid gas, and humic acid, which it contains, or may 
evolve after it has been applied; and in the second by the quantity of water 
which it is able to take up and retain. This second test alone must not be 
trusted to, otherwise bog-earth, a very sterile substance in its undecomposed state, 
might be decided to be the best of all manures; nor will the the first test always 
answer, otherwise chalk would appear to be an excellent manure; and so it might 
be under peculiar circumstances, and would be always if it could be brought to 
take up and retain enough of water to dissolve a portion of it, which it can only 
do by means of the humic acid. By using Mr. Johnson’s apparatus, fig. 2, 
already described, the capacity of any manure to take up and retain water may 
be easily ascertained.” 
Composts. —It having been found, th&t the most fertile soils are those which 
contain a mixture of various ingredients, the conclusion was obvious, that soils 
artificially composed of the same or similar materials, would prove similarly fer¬ 
tile. This gave origin to the various compositions, termed composts, whose value, 
must of course be tried, like that of individual manures, by the leading tests of 
their proportional quantity of carbonic acid gas, and humid acid, and their capa- 
D 3 
