266 
than we suppose in the operator. Salts may be de- 
tected by the taste, or by the crystals formed in the 
evaporation; but, unless there is a decided saline 
taste, the whole may be considered as soluble humus, 
and the immediate fertility of the soil depends greatly 
on the quantity of it. To recapitulate what has 
been obtained,—we shall have the coarse grit in 
sleve No. 1; the sandin Nos. 2 and 3; the fine earth 
separated in the tubes Nos. 1 and 3; the humus in 
tube No. 2 and on the filtering-paper; and the solu- 
ble parts in the evaporating-dish. All these sub- 
stances must be well dried over the fire, as was done 
with the soil at first, and each separate part accu- 
rately weighed. The sum of them ought to be equal 
to the original portion of soil subjected to analysis 
after the water was driven off; but there always is 
a loss, even with the most experienced analyser. 
This loss will be principally in the finer parts, which 
are dissipated in the operation. 
‘* But the analysis is not yet completed: we have 
separated the sand, clay, and humus; but there may 
be a portion of carbonate of lime, in the form of 
sand, or of finely-divided earth mixed with the other 
earths. To ascertain this, each portion, excepting 
the humus, is put into a separate cup, and a little 
muriatic acid, diluted with four times its weight of 
water, is poured on it. If there is any effervescence, 
it shows the presence of carbonate of lime; diluted 
acid is then added gradually, as long as the efferves- 
cence is renewed by the addition. When this ceases, 
and the water continues to have an acid taste, more 
pure water is added, and each portion separately 
filtered, dried, and weighed. The loss of weight in 
each gives the quantities of carbonate of lime dis- 
solved by the muriatic acid, and which has passed 
with the water in the form of muriate of lime.* The 
different weights being now collected, the re- 
sult of the operations might be set down. There 
may be many mineral substances in the soil which 
this mode of analysing will not detect; and some of 
these may materially affect the fertility. In most 
cases there will be something to indicate the pre- 
sence of metals. Iron abounds in most soils: when 
the quantity is considerable, it will be detected by 
pouring a decoction of gall-nuts into the water which 
has washed the earth; it will immediately become 
of a bluish dark colour. The other metals are not 
of frequent occurrence. Sulphate of lime or gypsum, 
and also magnesia, are found in some soils; but the 
separation of them can only be effected by those who 
are well acquainted with chemistry: they fortunately 
occur very seldom, and the places where they are 
found are generally well known. For all practical 
purposes, it is sufficient to ascertain the proportion 
of sand, clay, carbonate of lime, and humus which 
any soil contains. Many soils which have been 
highly manured contain portions of undecomposed 
vegetable substances, and fibres of roots; these will 
be found mixed with the coarser earths separated by 
the sifting: not being a part of the natural soil, they 
need not be taken into the account; but they may 
be separated by washing the earths, as they are 
much lighter, and will come over in the first decan- 
tations. ‘They may be dried and weighed, and the 
quantity set down in the result, if it is desirable. 
Some very barren sands, containing very little argil- 
laceous earth or humus, may readily be known by 
the copious sandy deposit which they rapidly make 
when diffused through water. Good natural loams 
are not so easily judged of; but the preceding mode 
* It may be objected to this mode of ascertaining the car- 
bonate of lime, that the muriatic acid will dissolve iron, anda 
ortion, however small, of alumina as well as carbonate of 
ime, and that the collecting the carbonic acid evolved is a 
more exact measure of the quantities of the carbonate. This 
may be admitted ; but we repeat that we only propose a simple 
and easy analysis, which will approximate to the truth, and 
not by any means a perfect one. 
pene verneaes 
SOIL. 
of analysis will in general detect their intrinsic value. 
When a soil contains peaty matter, it is easily dis- 
covered by the irregular black particles which are 
visible in it. Peat differs from humus only in being 
in a different state of decomposition, and containing 
a considerable portion of tannin; when acted upon 
by lime or alkalies, and brought into a state of 
greater decomposition, it is not to be distinguished 
from humus in its qualities. 
‘* The process which we have described, simple 
as it is, may yet be too tedious for the farmer who 
is desirous of speedily comparing different soils; and 
we will indicate a still simpler method of ascertain- 
ing, nearly, the composition of a soil and a simple 
instrument by which it may be done. ‘Take a glass 
tube, 3 of an inch in internal diameter, and 3 feet 
long; fit a cork into one end, and set it upright; fill 
it half full of pure water; take nearly as much water 
as has been poured into the tube; and mix with it 
the portion of soil which is to be examined, in quan- 
tity not more than will occupy 6 inches of the tube; 
pour the mixture rapidly into the tube, and let it 
stand in a corner of a room, or supported upright in 
any way. In half-an-hour it may be examined. The 
earths will have been deposited according to the size 
and specific gravity of their particles. The portion 
still suspended in the water may be allowed to settle; 
and there will appear in the tube layers of sand, 
clay, and humus, which may be measured by a scale, 
and thus the proportions nearly ascertained. When 
a farmer is about to hire a farm, of which the quality 
is not well known to him, he may be much assisted 
in his judgment by this simple experiment, if he has 
no time or opportunity for a more accurate analysis. 
For the glass tube may be substituted one of tin or 
zinc 2 feet in length, with a piece of glass tube, a 
foot long, joined to it by means of a brass collar or 
ferule with a screw cut in it, which is cemented to 
the glass, and screws on the metal tube; and thus 
the instrument may be made more portable. When 
the water has been poured off, and the earths only 
remain, the cork may be taken out, and the contents 
pushed out on a plate, by means of a rod and a plug 
which exactly fits the internal diameter of the tube. 
They may thus be more particularly examined.” 
‘‘ The first problem in an agricultural analysis,” 
says Dr. Ure, ‘is to find the proportion of calcareous 
matter, as carbonate and phosphate of lime. This 
may be easily solved with the aid of the instrument 
figured below, which may be called the Limestone 
Meter. A, is a cylinder of glass, two inches in 
diameter, and fourteen inches long, graduated on 
one side with a scale, into spaces of 100 water. 
grain measures from 0 to 12,000, marked 10, 20, 
30, &c.; and graduated on the other side into spaces 
of 240 water-grain measure, each. The former 
scale is used for the analysis of all sorts of alka~ 
line carbonates, and also of acids; the latter is 
adapted to the direct analysis of carbonate of lime 
and marls, and indirectly to that of phosphate of 
lime and carbonate of magnesia. The cylinder A, 
has a tubulure in its side near to the bottom; this is 
closed with a cork, in the axis of which a short glass 
tube is cemented, hooped externally to a collar of 
caoutchouc E, which serves as a joint to the upright 
long glass tube B, held near its upper recurved end 
in a hooked wire. The top of the cylinder A is 
closed with an elastic cork, through a perforation in 
which the taper tail of the little phial C passes air- 
tight. The small tube F, open at both its ends, is 
cemented on its outer surface, into the bottom of the 
phial C, so as to close it, while the tube itself opens 
a free passage to gas, from the shoulder of the phial, 
down into the cylinder A. The mouth of the phial 
C is shut with a cork, through which the small end 
of the tube D passes air-tight. The tube D is gra- 
duated into spaces of 10, 20, &c., water-grain mea- 
