100
Molesworth’s pocket-book
Note5 on Lime. •
CLASSIFICATION OF LIMESTONES. (VlCat.)
1 Fat Lime.—Pure lime which does not set in
water 2. Poor Lime.—Mixed with eand, which
does not alter its condition. 3. Slightly Hydraulic
Lime, containing 8 to 12 per cent, of silica, alu-
iniuia, magnesia, iron, aad manganese, sets slowly
in water 4 Hydraulic Lime, containing 12 to
20 per cent, of the above ingredients, sets in water
in «ix or eight days. 5, Eminently Hydraulic
Lime, containing 20 to 3Ü per cent, of the above,
sets in two to four days. 6 Hydraulic Cement,
eoutaiiiing 30 to 50 per cent, of argil, sets m a
few minutes, and. attains the hardness of stone in
a month. “Puzzolana” and “Trass,” volcanic
products, if mixed with pure lime, make hydraulic
mortars.
ROUGH INDICATIONS OF LIMESTONES.
They dissolve wholly or partly in weak acids,
with brisk effervescence. They are nearly inso-
luble in water They can be scratched with an
iron point.
sough analysis of limestone (Rourkee Treatise).
1 . Pound the sample, and pass it through a
fine sieve. 2. Put 150 grains into a tumbler, and
pour gradually on it diluted hydrochloric acid, stir-
ring and adding the acid until effervescence ceases.
3. Filter through blotting paper, and then wash
by pouring at least a quart of water through it.
4. Carefully collect the remainder, dry, and weigh
it; its weight deducted from 150 grains will give
the weight of carbonate of lime. 5. Wash°the
remainder repeatedly with decantation to remove
the lighter particles of clay, then dry and weigh
the sediment, which may be assumed to be sand.
112 grs. carbonate of lime, 9 of clay, and 29 of sand
will be a fair proportion for general purposes.