1819.) Dr. Thomson on Oxymuriate of Lime. 183 
detailed account of the experiments till some future opportunity ; 
for more time than I can at present command would be requisite 
to disentangle the useful from the immaterial or indecisive expe- 
riments, with which they are mixed in the journal which was 
written down at the time. 
1. Oxymuriate of lime, when recently prepared, is quite dry to 
the feel. It has a peculiar smell, bearing some relation to that 
of chlorine, but not so offensive. Its taste is hot and astringent. 
The hot taste is probably owing to the uncombined quick-lime 
contained in the powder; for when the oxymuriate of lime is 
dissolved in water, the taste of the solution is merely astringent. 
2. Fifty grains of the powder being digested in a sufficient 
quantity of water to dissolve the soluble part of the salt, and — 
poured upon a filter, left a quantity of lime, partly in the state of 
quick-lime, and partly in the state of carbonate. Concluding 
that the carbonic acid had been absorbed during the drying of 
the lime, I digested the insoluble residue from other 50 gr. of 
the salt in diluted sulphuric acid, evaporated the liquid to dry- 
ness, and exposed the sulphate of lime, thus obtained, to a red 
heat. It weighed 27:8 gr. indicating 11-68 gr. of lime. 
3. The portion of the oxymuriate of lime dissolved in water 
reddened turmeric paper, and when left exposed to the air, a 
crust of carbonate of lime was formed in the surface of the 
liquid. Hence it was obvious, that besides the bleaching salt, or 
oxymuriate of lime, the water had dissolved likewise a portion of 
lime, and was, therefore, in the state of lime water. 
4. The solution obtained by digesting 50 gr. of the bleaching 
powder in water and filtering, was mixed with an excess of 
sulphuric acid, evaporated to dryness, and exposed to a red heat. 
The sulphate of lime formed weighed 31°5 gr. mdicating 13:23 gr. 
of lime. 
5. Another similar solution, obtained from 50 er. of the bleach- 
ing powder, was precipitated by nitrate of silver. The chloride 
of silver obtained weighed 55 gr. indicating 13°56 gr. of chlorine. 
6. Now if we consider the bleaching salt to be a combination 
of chlorine and lime, or a chloride of lime, as I shall afterwards 
show it to be, we shall find the quantity of uncombined lime in 
the solution by subtracting from the total quantity of dissolved 
lime that portion of it which is in combination with the chlorine. 
This quantity may be found as follows : 
The weight of an atom of chlorine is 4°5, and of an atom of 
lime 3-625 ; the quantity of chlorine in 50 gr. of the bleaching 
owder is 13-56 gr.; therefore, 4:5 : 3°625 :: 13°56 : 10°92 = 
me united to the chlorine, 
Total lime in the solution. ...... ... 13°23 
Lime united to the chlorine. ........ 10°92 
Uncombined lime in the solution... = 2°31 , 
