2 Dr. IJre on Chloride of Lime. 



pher, " in order to have a clear view of these compounds of 

 oxymuriatic acid and lime, it appears that the dry oxymuriate 

 of lime, or, as it should be called, hyperoxy muriate, consists 

 of 1 atom acid, 2 of lime, and 6 of water ; namely, 



1 of oxymuriatic acid . . 29 or 23.2 



2 of lime, 48 or 38.4 



6 of water, 48 or 38.4 



125 100.0 



When the salt is dissolved in water, one half of the lime is 

 precipitated, and the liquid contains a solution of oxymuriate 

 of lime, the proportions of the elements of acid and base being 

 then, 



1 atom acid, . . . 29 or 54.7 



1 atom lime, 24 or 45.3 



53 100.0 *." 



These atomic numbers of Mr. Dalton being divided by 7, are 

 reducible to the oxygen radix. As the means of analysis, he 

 employed, in preference, a solution of the green sulphate of 

 iron, adding it to a given weight of the oxymuriate, as long as 

 any smell of chlorine was perceptible, or till the power of the 

 chlorine was consumed in converting protoxide of iron into per- 

 oxide. " If the sulphate is deficient," says he, " a strong 

 smell of oxymuriatic acid accompanies the mixture; whence 

 more sulphate must be added, till the mixture, on due agita- 

 tion, ceases to emit the fumes of oxymuriatic acid : if too much 

 sulphate is put in, then more of the acid liquor," (oxymuriate 

 of lime solution,) " must be added by degrees, till its peculiar 

 odour is developed t." Dr. Thomson says that he tried this 

 test, but found it unsatisfactory- I also tried it, and found it 

 not only unsatisfactory, but highly insalubrious ; the applica- 

 tion of the nostrils to the mixture, in order to ascertain the 

 neutral point, necessarily causing the inhalation of chlorine. 

 In the sequel of his paper, Mr. Dalton advises the bleacher to 

 use a tri-hydrate of lime ; that is, a compound of nearly equal 



• Annals of Philos. II. p. 7. t Idem, p. 18. 



