CARBONATES. 



385 



SESQ.UI -CARBONATE. 



This name, as already implied, has been given to the salt just de- 

 scribed, and which is obtained by subliming 1 part of muriate of am- 

 monia, and 1 J of dry carbonate of lime ; if no loss were sustained, it 

 should contain equal quantities of carbonic acid, ammonia, and water; 

 but both ammonia and water are wasted by the heat, and it in fact 

 consists of about 55 acid, 30 base, and 15 water, corresponding very 

 nearly with the constitution, of acid, 3 proportions, =66, base, 2 

 =34, water, 2 = 18=118, for its equivalent. This is Dr. Henry's 

 view, and if correct, there seems to be no occasion, in this case, for 

 a name implying half a proportion ; for 66 is obviously a multiple of 

 22, as 34 is of 17.f 



CARBONATE OF AMMONIA. 



1 . PREPARATION. There is but one mode of forming the carbo- 

 nate containing one equivalent of each of the principles, and that is by 

 mingling carbonic acid gas I volume, and ammonia 2, over mercury ; 

 or in a dry bottle, the gases coming from different vessels ; the solid 

 carbonate is precipitated, and crystallizes in plumose rays on the 

 interior of the vessels. 



Either of the arrangements represented by the annexed figures 

 will answer very well for this experiment ; muriate of ammonia and 

 lime being in one of the retorts or flasks, and marble powder and 

 diluted sulphuric acid in the other. A mild heat is applied to the 

 vessel containing the materials for affording ammonia, and the mid- 

 dle vessel receives the condensed gases. 



2. COMPOSITION. Acid, 56.20, 1 proportion, 22 

 Alkali, 43.80, 1 " 17 



100.00 

 This salt is unknown in the shops. 



39, its equivalent. 



* Sesqui Latin, one and a half. 



t Dr. Thomson, who introduced the term sesqui, to provide for cases, where there 

 appears to he half an equivalent, admits fractions of atoms as a provisional mode of 

 expression, although, as he distinctly explains, from the very nature of atoms, they 

 do not admit of fractions. First Principles, Vol. I, p. 32. 



49 



