Dr. Ure on Disinfection. 87 



muriatic acid, that quantity of the said chloride would have 

 evolved about 145 grains, or 190 cubic inches of pure gas. I 

 may remark, that few samples of the bleaching-powder found 

 in the market are impregnated like the above with fully 29 

 per cent, of chlorine, and the stuff retailed in many shops 

 under that name seldom contains more than 16 per cent. 

 As for the liquid chloride of lime, the two-shilling bottles 

 occasionally possess no more virtue than would be found in 

 two-pennyworth of Messrs. Tennant's dry bleaching salt. 

 Nothing, therefore, can exceed in absurdity the fashionable 

 nostrum for disinfecting apartments charged with contagious 

 fomes, by placing in them one or more saucers filled with 

 chloride of lime. To place this dangerous fallacy in the 

 plainest light, I need merely state that moist litmus paper may 

 be hung for a day a very few inches above such a saucer 

 without perceptibly losing colour; whereas the affusion of a 

 few drops of muriatic acid on the same chloride, even after the 

 above period, will instantly blanch the suspended paper. 



It has been supposed that the carbonic acid present in the 

 atmosphere displaces the chlorine from the lime ; but how 

 slowly and insignificantly the preceding experiment may show. 

 The following facts have been long before the medico-chemical 

 world. 6 After passing a current of this gas (carbonic acid) 

 for a whole day through the chloride diffused in tepid water, I 

 found the liquid still to possess the power of discharging the 

 colour very readily from litmus paper *.' 



Chloride of lime laid out in the air passes rapidly into a 

 deliquescent paste, consisting of muriate of lime, and lime with 

 an obscure displacement of oxygen. If the chloride be sur- 

 charged with chlorine, it speedily gives off the excess and 

 becomes commercial chloride. The best manufacturers, aware 

 of this circumstance, never push the impregnation beyond a 

 certain pitch; in which state the chloride does not sponta- 

 neously emit in the air one-thousandth part of its condensed 

 chlorine. To pretend, therefore, to suffocate the hydra of con- 

 tagion by subjecting it to the simple smell of chloride of lime 



** On the Manufacture and Composition of Chloride of Lime, by Dr. Ure, 

 Quarterly Journal of Science and the Arts, for July, 1322. 



