105 
ANALYSIS OF SOILS. 
"We now conclude the subject which we quitted at page 59, No. 75. The 
Reverend Author of the successful prize Essay completes (as we have seen at 
p. 59) his processes of separation by repeated washings of the fine substances depo- 
sited in the lowest partition of his compound sieve, in two separate glass tubes ; 
the first of which retains the finest aluminous earth, while the other receives the 
humus ^ or light floating vegetable matter, contained in the several washings of 
the fine substances. 
This humus is at length deposited on a filter, through which the water passes. 
— " The mud which remains is dried over the fire and weighed. This is the most 
important portion of the soil. The fine earths in tube No. 1 will consist of very 
fine particles of sand, clay, and perhaps carbonate of lime. The sand will appear 
deposited in the bottom of the tube ; the clay (alumina) may be easily diffused in 
the water above it, by stirring it carefully with a small rod without touching 
the sand. It may then be decanted off with the water into another tube, (No. 3,) 
and allowed to settle : this part of the operation may be carried to a greater degree 
of perfection, by great care, and by examining the results occasionally witli a small 
microscope ; but for all common practical purposes, it is sufficient to separate the 
vegetable earth from the mineral, and the visible particles of sand from the finer." 
We cannot sufficiently thank this able essayist for his exertions to simplify 
analysis : heretofore recourse has always been had to pure chemistry ; and conse- 
quently ninety-nine practical men of a hundred — among gardeners as well as 
farmers — have been utterly deterred from experimentizing. Still, however, we shall 
see, as we proceed, that an analysis can never be made complete without the aid of 
chemistry ; although that process which proved the most knotty and intractable to 
the chemist (we mean the dissolution and separation of the pure clay, or alumina) 
is relieved from its greater difficulty by the able manipulation of Mr. Rham. We 
render, therefore, our unqualified thanks to that gentleman, for the assistance which 
he thus has afforded to the analyst. 
Saline substances are traceable in soil ; to detect these, we read that — " All the 
water in which the earths have been diffused and washed, is collected and passed 
through filtering paper, and then set over the fire in a common saucepan. It 
is boiled away gently until it is reduced to a small portion which begins to look 
turbid. The complete evaporation is finished in an evaporating-dish, as slowly as 
possible, and the residue is the soluble matter contained in the soil. It will 
be sufficient to dry and weigh this, as its further analysis would require more skill 
and chemical knowledge than we suppose in the operator. Salts may be detected 
by the taste, or by the crystals formed in the evaporation ; but unless there 
VOL. VII. NO. LXXVJI. P 
