280 MR. H. GRIMSHAW ON BASIC CALCIUM CHLORIDE. 



The difference of the proportion of the constituents ac- 

 cording to the above formula, and according to that as- 

 signed by Rose, is therefore that corresponding to one 

 atom of water more or less. As the amount of water is 

 nearly 50 per cent, of the whole, this constituent will ex- 

 hibit the greatest difference, namely i'6i4. Accordingly, 

 the numbers above will be found to agree with the formula 



O < + 7H z O, which loses on heating 49*179 per 



v- v>a v^i 



cent. The number found by Rose (49*084) agrees very 



nearly. 



The salt is perfectly stable for any length of time if kept 

 out of contact with the air. It may be also kept unaltered 

 in the mother-liquor for some time. In the air it decom- 

 poses, absorbing carbonic acid and water. Over sulphuric 

 acid in vacuo or in air, or over quicklime, it parts with a 

 portion of its water of crystallization. Both these circum- 

 stances interfere with the exact drying of the salt. 



With water it decomposes into calcium hydrate and 

 calcium chloride : 



20 {^ H + 2H 2 = 3 Ca(OH) 2 + CaCl z . 



By the substitution of hydrobromic for the hydrochloric 

 acid in the preparation of the salt, I expect to obtain a 

 corresponding bromine compound. 



