On the Analt/sis of Soils. 
615 
is of very uniform texture and appearance; being a finely comminuted 
friable loam, quite free from stones, consisting of a fortunate mixture 
of fine siliceous sand, clay, oxide of iron, and carbonate of lime, with 
minute proportions of phosphate of lime and magnesia, but very little 
organic matter. It would seem, therefore, to derive its principles of 
fertility chiefly from tiie atmosphere, and the emanations from the sub- 
soil. 
The specific gravity of the soil, in its average state of dryness, is 2"2 
to -water called TOj indicating the presence of but little vegetable 
matter. 
100 parts of it collected after a period of ordinary dry weather lose 
ir2 by a steam heat of 212°, and readily re-absorb that portion of 
moisture when again exposed to damp air. When the dried residuum 
is calcined at a dull red heat, six parts of vegetable substance are 
burned away ; at a higher temperature the carbonate of lime would be- 
come calcined, and cause an additional loss of weight, which might 
inconsiderately be mistaken for organic matter. 
The first problem in an agricultural analysis, is to find the proportion 
of calcareous matter, as carbonate and phosphate of lime. This may 
be easily solved with the aid of the following instrument (see page 621), 
which may be called the Lime-stone Meter, one of which was presented 
and explained by me to the Council of the Royal Society of Agriculture 
on the 29th of May last. 
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 alkaline carbonates, 
and also of acids ; the latter is adapted to the direct analysis of car- 
bonate 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 W'ith 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 sur- 
face, 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 graduated 
into spaces of 10, 20, &c., water-grain measures 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 
