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MR HENRY HOW ON CERTAIN SALTS AND 
Bicomenate of Soda. 
Comenic acid was dissolved in a tolerably strong solution of caustic soda by 
boiling; the fiuid on cooling deposited two forms of crystals, one in mammillated 
masses, the other in transparent prisms half an inch in length. On washing the 
mixture with a little cold, and resolution in boiling, water, no deposit was obtained 
on cooling, even after the lapse of some hours; but on evaporation of the fiuid to 
about two-thirds of its bulk, groups of mammillary crystals appeared, which when 
magnified were found to consist of four-sided elongated prisms. From this it 
appears that the salt is much more soluble than either the potass and ammonia 
salt, and cannot be employed with advantage in the preparation of comenic acid. 
It has an acid reaction, and is anhydrous; its analysis is subjoined. The soda 
was determined by simple ignition, and subsequent weighing of the carbonate of 
soda produced 
{ 6-020 grains dried at 212° gave 
1:753  ... carbonate of soda. 
The per-centage of soda calculated from this experiment is 17:09 : 17-41, being 
that corresponding with the formula 
NaO, HO, ©,, H, 0,. 
It is obvious, from the foregoing experiments, that neutral salts of comenic 
acid with the fixed alkalies or with ammonia do not exist in the dry state. That 
this is not the case with reference to the alkaline earths, I shall now proceed to 
shew. 
Salts of Lime with Comenic Acid. 
Finely-powdered comenic acid, mixed with water and an excess of carbonate 
of lime, decomposes the earthy salt with effervescence, in the cold. When the 
liquid is boiled for some time, then filtered and allowed to stand, a few rhombic 
crystals appear; but by far the larger proportion of the acid remains on the filter 
in combination with the lime, mixed with the excess of carbonate employed. The 
crystals were in very small quantity; they consisted doubtless of the acid salt, 
which I obtained more conveniently in another way. 
Bicomenate of Lime-—When a cold, saturated, aqueous solution of bicomenate 
of ammonia is added to a solution of chloride of calcium, brilliant crystals soon 
begin to appear which gradually increase in quantity. They are, though small, 
perfectly defined transparent rhombs; they dissolve readily in boiling water, and 
are deposited on cooling of a larger size than when first obtained. In the follow- 
ing analysis the substance was dried at 250° Fahr., as it was found that the whole 
water of crystallization was not expelled at 212°, or only after the lapse of a very 
long time. The lime was determined as sulphate, by ignition with a few drops of 
sulphuric acid, as the salt swelled up inconveniently when heated by itself. 
4-512 grains dried at 250° Fahr. gave 
6°755 ... carbonic acid, and 
0-788... water. 
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