CHEMICAL MANUFACTURES IN GLASGOW, ETC. 
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other color may be superadded- Tartaric acid is obtained 
from cream of tartar, by throwing down the tartaric acid by 
means of lime, and afterwards decomposing the tartrate of 
lime by means of sulphuric acid, and cry stallizing the tartaric. 
At the same manufactory may be seen a pretty and simple 
process, by which the carbonate of soda is converted into ses- 
quicarbonate. By simply exposing it dry, and in powder, in 
an atmosphere of carbonate acid gas, it absorbs the requisite 
quantity to be converted into sesquicarbonate. 
8. It is hardly proper to mention the manufactory of acetic 
acid from wood, which has been carried on for many years, 
by Mr. Turnbull, because the first part of the process is car- 
ried on at a distance, the distillation of the wood. To free 
the acetic acid from the tar, which destroys its flavor and 
taste, the acid is combined with lime, and the acetate of lime 
exposed to a heat sufficiently high to char the foreign bodies 
with which it is impregnated, the acetic acid being capable of 
resisting a higher temperature, without decomposition, than 
most compound vegetable bodies. The acetate of lime thus 
purified is decomposed by sulphuric acid, and the acetic acid 
obtained by distillation. By this process it may be obtained 
very strong. The author possesses it composed of one atom 
acetic acid and one atom water. When of this strength it 
crystallizes in winter, but becomes liquid again in summer. 
In the same manufactory there is another liquid prepared, 
namely, pyroxylic spirit, now well known. 
A most interesting set of experiments on it has been made 
by Dumas, who has distinguished its basis by the name of 
methylene, and has discovered various new compounds which 
it is capable of forming. 
9. Another chemical manufacture of considerable impor- 
tance, and which the author believes to be peculiar to Glas- 
gow, is Iodine. A few years ago there were no fewer than 
ten manufactories, in each of which it was made to a consid- 
erable extent ; but as iodine is only used in medicine, the 
sale is necessarily limited, and most of these works are now 
abandoned. The process followed by all the makers was a 
