&> 
S 
tiitine “| LOTT il i} 
3 § 
Laer 
cS) 
S 
= 
S 
S 
PEO TTT 
INCHES 
CE I ENRON TANS. a Heh GRY SREY feoeks'( BS.5 ad SAL 
sures up to 250, and is closed at top with a stop- 
cock. Its lower and capillary extremity is recurved. 
In ascertaining with this instrument the proportion 
of real carbonate of lime, in any limestone, marl, or 
soil, proceed as follows :—Lift out the phial C, and 
pour water into the cylinder A till it stands about 
half an inch below the line marked 0, and fill up this 
space with common linseed-oil. Restore the phial 
SOIL. 
267 
C to its place, pressing it in air-tight. Then take 
out its cork with its graduated tube, and introduce 
into the phial as many grains’ weight of the soil or 
marl as it is proper to operate upon. Of an average 
limestone 50 grains are sufficient, because the mag- 
nified scale of the lime-proof is adapted to the analy- 
sis of 50 grains of pure carbonate of lime. Of soils 
and marls, 100, 200, or even 500 grains, may be 
taken, because these substances will rarely contain 
one-tenth their weight of carbonate of lime. But 
as the result may always be obtained within five 
minutes, at the cost of half a farthing, several suc- 
cessive experiments may be made on different weights 
of the sample. Having introduced the proper weight 
of the object into the phial, cover it with water, till 
this stands a little above the point to which the re- 
curved tube descends. Holding D in the hand, dip 
its bent point into a phial containing ordinary muria- 
tic (hydrochloric) acid, diluted with its own bulk of 
water, and applying the mouth to the opened stop- 
cock, suck up the acid into the tube till this be about 
two-thirds full, then turn the key of the cock before 
it is taken from the lips, and the acid will not drop 
out when the tube is held upright. Replace the 
cork with its tube D in the phial C. Detach the 
long tube, B, from its wire-rest with the left hand, 
and hold its curved extremity above an empty basin; 
then with the right hand open the stop-cock of D, 
to let a little acid run down upon the marl, but shut 
it almost instantly again, lest too much acid should 
escape, and cause so brisk an effervescence as to oc- 
casion an overflow of the mixture into the small 
tube, F. The disengaged carbonic acid escapes 
through the tube F, presses on the surface of the oil 
in A, and causes a stream of water to flow from the 
tube B, into the subjacent basin. When the water 
ceases to run, open the stop-cock again, when more 
acid will descend, cause a fresh extrication of gas, 
and a further flow of water. ‘The curved end of the 
tube B should be progressively lowered, as the oil 
falls in A, so as to maintain its level and that in the 
tube in the same horizontal plane. Whenever gas 
ceases to be extricated by the muriatic acid, the ex- 
periment is completed, and the number on the lime- 
meter scale opposite to the upper surface of the oil, 
denotes the number of grains of carbonate of lime, 
in the quantity of limestone, marl, or soil, put into 
the phial C for experiment. A little carbonic acid 
gas remains condensed in the muriatic solution, but 
this is not more than equivalent to the bulk of liquid 
acid introduced into the capacity of the apparatus; 
so that no compensation need be made in this ac- 
count. For the purpose of minute chemical research, 
that portion of gas may be expelled by surrounding 
the phial C with a cloth wrung out of hot water, and 
the volume of dilute acid added, may also be taken 
into the account. Thus the composition of carbon- 
ates by an acid, and of acids by a bicarbonate, may 
be determined by means of this instrument with 
equal rapidity and precision. The contents of the 
phial may be poured out into a porcelain capsule, 
gently heated, and thrown ona filter. The lime of 
the carbonate, as well as the phosphate of lime and 
the magnesia, will pass through in solution along 
with a very little iron. On super-saturating the 
acidulous liquor with water of pure ammonia, phos- 
phate of lime (if present) will fall, and may be drained 
on a filter and dried. Taken off the dried filter, and 
digested with a little dilute sulphuric acid, sulphate 
of lime will result, characterized by its entire insolu- 
bility in dilute alcohol. Hence the sulphate washed 
with vinous spirits, dried and calcined, will represent 
by its weight one-fifth more than the original weight 
of the phosphate. By the action of the sulphuric 
acid, the iron precipitated by the ammonia with the 
phosphate is got rid of. The magnesia, unless its 
proportion had been very great, will all remain dis. 
