On the Alkalies of Commerce. 3 1 3 



Lastly, we see the reason why from a mixture of Hine 

 and of supersaturated carbonate of potash, with too little 

 water, the first lixivium, which may be filtered, will be effer- 

 vescent, while that which may be obtained from washings, 

 i. e. by the addition of a new quantity of water, will come 

 off entirely caustic. 



These alternatives might take place upon the execution of 

 the second of the processes, already quoted, of M. Fourcroy, 

 because the proporlion of waier is then indeterminate , while 

 in the first process, if it be equal to eight or ten tunes the 

 total weie;ht of the supersaturated carbonate of potash and 

 lime, it is evident that we ought consequently to obtain 

 potash totally deprived of carbonic acid, if we "have never, 

 by the ebullition prescribed of two or three hours, reducc:d 

 the proportion of water to a less quantity than seven ti;iies 

 tlie weiirht of the supersaturated carbonate of potash: for 

 my own part, I am convinced that an ebullition of a few 

 minutes is at all times sufficient. 



Pulash exists i?i all Lime which is burnt hy a Wood Fire, 

 T shall now proceed to announce some facts connected 

 Vviih the preceding observations. 



So long as;o as the vear 179'i, my brother and I observed 

 that lime, when burnt by means of wood, contained potash : 

 this will not appear surprising when we consider the great 

 lightness of some particles of ashes, which may be called 

 Jiowei-a uf ashes : there is no wood fire, let it be ever so 

 small or moderate, that does not emit these flowers, and we 

 see them attached to the kitchen utensils which are heated 

 upon a wood tire. Their alkaline property will be evident 

 if we first moisten the tip of the finger with a little saliva, 

 and afterwards lay it gently upon the vessels to which these 

 flowers are attached. On afterwards applying the finger to 

 the tongue, a very decided alkaline taste. will be perceived. 

 It may be easily conceived, therefore, that in a violent fire, 

 such as that of a lime-kiln, the current of air which traverses 

 it carries these light ashes through the pieces of calcareous 

 atones. The earthy part of these a^jhcs stops at the exterior 



of 

 & 



