OF SODA. 267 



1 atom carbonic acid 2-?5 



1 atom soda . 4 



10 atoms water 1 1-2.5 



18 



When the salt is crystallized in hot water, the 

 shape of the crystals is different ; and the quan- 

 tity of water of crystallization is less. 



4. Sesquicarbonate of soda. This salt is found s 



-n i , bonate 



native in Barbary, where it is known by the 

 name of trona. It constitutes hard masses, which 

 do not deliquesce in the air ; and is said to be 

 employed in the north of Africa, where rain sel- 

 dom falls, for building the walls of houses. It 

 is manufactured in London, for the use of the 

 soda-water makers ; and is sold in the state of a 

 white powder. I have tried to crystallize it, 

 without success. Its constituents are as fol- 

 lows : 



11 atom carbonic acid 4-125 



1 atom soda . 4 



2 atoms water 2-25 



10-375 



This constitution was first pointed out by Mr. 

 Phillips. 



5. Bicarbonate of soda. This salt was made 

 and analyzed many years ago by Rose, and af- " d 

 terwards by Berthollet. I tried to form it in a 

 Nooth's apparatus the crystallization of the salt 



