On the Alkalies of Commerce. 3 1 5 



This is the reason why some sugar-refiners take great pams, 

 and expend a great deal of money, for a first lime water, 

 which they might obtain by a little potash and lime. 



Lime water is recommended by some oculists : it is for 

 them to consider whether it is proper that it slwuld contain 

 caustic potash, i. e. the caustic stone. This observation is 

 equally applicable to the internal use of lime water, pre- 

 scribed by some physicians. 



In chemical experiments, therefore, such as making the 

 precipitate and sulphuret of lime, 8cc., we must employ 

 lime burnt with coal, or it must be washed if it has been 

 burnt with wood. 



Origin of Natural Soda, as it is called. 

 The efflorescences of carbonate of soda, found under the 

 arches of the Pont-neuf, at Paris; those of the cellars at 

 Dieppe and other maritime places, are no longer objects of 

 astonishment. A few years ago, when at Dieppe, I had 

 occasion to ascertain the origin of these efflcrcscences mixed 

 with sulphate of soda. I descended into the cellar, under 

 the kitchen, of my paternal residence, where in my infancy 

 I had seen the linen of a nunerous family washed. The 

 arch of this cellar had been formerly plastered. The 

 greatest part of this plaster was now detached ; but where 

 it still remained there was sulphate of soda, while beside it 

 there was only carbonate of soda. The origin of these two 

 salts was no longer a mystery to me ; for, independently of 

 the potash existing in the lime of the vault, the leys, when 

 the linen was washed, had penetrated the masonry; they 

 had there met with kitchen salt, which had been conse- 

 quently decomposed; hence the carbonate of soda. This 

 last, wherever it found sulphate of lime, had given place to 

 the formation of sulphate of soda. 



It often requires but a slight degree of reflection, upon all 

 the circumstances which accompany results most extraor- 

 dinary in appearance, in order to explain the most striking 

 contrasts; and for this purpose a great number of iacts, hi- 

 therto ill explained, must be rcviesved. 



First 



