616 
On the Anali/sis of Soils. 
about half an inch below the line marked 0, and fill up this space with 
common linseed-oil. Restore the phial 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, be- 
cause the magnified scale of the lime-proof is adapted to the analysis of 
50 gi'ains of puie 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 successive experiments may be made on different 
Aveights 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 recurved tube descends. Holding D in the hand, 
dip its bent point into a phial containing ordinary muriatic (hydro- 
chloric) acid, diluted with its own bulk of water, and applying the 
mouth to the opened stop-cock, suck uj) 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 up- 
right. Replace the cork with its tube Din the phial C. Detach the long 
tube, B, from its wire-rest with the left hand, and hold its curved ex- 
tremity 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 occasion an overflow of the mixture into the small 
tube, F. The disengaged carbonic acid escapes through the tube F, 
jiresses on the surface of the oil in A, and causes a stream of water to 
flow from the tube B, into tlie 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 
platie. Whenever gas ceases to be extricated by the muriatic acid, 
the experiment is completed, and the number on the lime-meter scale 
opposite to the upper surface of the oil, denotes the number of grams 
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 tlie bulk of liquid acid introduced into the capacity of the apparatus ; 
so that no compensation need be made in this account. For the pur- 
pose of minute chemical research, that portion of gas may be expelled 
by surrounding the ])hial C with a cloth wrung out of hot water, and 
the volume of ddute acid added, may also be taken into the account. 
Thus the composition of carbonates by an acid, and of acids by a bi- 
carbonate, 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 on a filter. The lime of the carbonate, as 
well as the phosphate of lime and the magnesia, will pass through in so- 
lution along with a very little iron. On super-saturating the acidulous 
