144 Experiments upon the 



This proves that the oxalic acid employed contained about 

 half its weight of the water of crystallization, and that the 

 salt of cinchona only contains a small quantity of lime; be- 

 cause in 27 parts of oxalate of lime there is more than 13 

 parts of this earth. 



After having thus separated the lime from this salt by the 

 oxalic acid, I allowed the liquor to evaporate spontaneously 

 in the air : it was reduced to the form of a very thick syrup, 

 without giving any sign of crystallization for more than 

 eight days; but having stirred it with a piece of glass, in order 

 to extract a part of it, which I intended to submit to a trial, 

 I was astonished to find, some minutes afterwards, that the 

 liquor was crystallized into a hard mass, formed of a great 

 quantity of divergent laminse from several very distinct cen- 

 tres of crystallization. 



It was of a slight brown colour ; its taste was extremely 

 acid and a little bitter, because the salt of cinchona I em- 

 ployed had not been perfectly purified. 



I shall, however, detail the properties which T recognised 

 in this acid : T cannot give long details upon this subject, 

 because I had only a very small quantity of salt of cinchona 

 at my command; 1 think, however, I examined it suffi- 

 ciently to be convinced that it is a peculiar acid hitherto 

 unknown. 



In its state of crystallization it has a very acid and a bit- 

 terish taste, as I have said above. 



It is perfectly well preserved in the open air; and it is 

 neither deliquescent nor efflorescent. 



Placed upon live coals, it melts very quickly, bolls up, 

 becomes black, exhales pungent white vapours, and leaves 

 but a very slight charry residue. 



It forms, with the alkalis and the earths, soluble and cry- 

 stallizable saltt. 



It does not precipitate the nitrates of silver, mercury, or 

 lead, as most of the other vegetable acids do. 



It can no longer be doubted that this acid is quite new to 

 us : on reflecting on the specific characters of the other ve- 

 getable acids known, we shall find that not one of them 

 unites all the properties of the above. 



In 



