Mr. R. Phillips on the Chlorides of Lime and Soda. 377 



The chloride of lime has long been known under the name 

 of oxymuriate of lime, or bleaching powder : it is prepared, as 

 is well known, by passing chlorine gas over hydrate of lime; 

 the resulting compound, put into water, yields the chloride of 

 lime in question ; it is also sometimes formed by passing the 

 gas into water containing lime in suspension : this chloride is 

 now proposed to be employed, and it appears with great suc- 

 cess, as a disinfecting substance. 



The existence of such a compound as chloride of soda, or 

 potash, has hitherto not been so clearly ascertained as tVt of 

 the chloride of lime. Two modes of preparing this compound 

 have been proposed, — one by M. Labarraque, and the other 

 by M. Payen ; the former passes chlorine gas into a solution 

 of carbonate of soda, while the latter proposes to decompose 

 chloride of lime by carbonate of soda. 



I have tried both methods, and both are very easy of execu- 

 tion. When chlorine gas is passed into the solution of car- 

 bonate of soda, it is very readily absoi'bed, and this absorption 

 takes place without expelling a particle of carbonic acid : the 

 solution has a faint smell of chlorine ; when heated scarcely 

 any chlorine is evolved, and the solution first acts as an alkali 

 upon turmeric paper, and then bleaches it : on the addition of 

 an acid, chlorine and carbonic acid gases are evolved. 



When evaporated until a slight pellicle appears, a mass of 

 fibrous crystals is soon formed, the consistence of which is 

 almost pulpy, owing to the retention of the solution by the 

 capillary attraction of the crystals. When these crystals have 

 been separated, the solution yields minute crystals of carbo- 

 nate of soda, pos«;essing the usual form of that substance. 



These filamentous crystals are too minute to admit of any 

 examination of their form: they appear to me to consist of 

 chlorine, carbonic acid, and soda, or chlorine in combination 

 with carbonate of soda ; when put into a solution of indigo in 

 sulphuric acid, they immediately decolorize it, by the evolution 

 of chlorine, accompanied with carbonic acid. I have not yet 

 had an opportunity of analysing this compound ; I find, how- 

 ever, that whilst drying by exposure to the air, it loses so much 

 chlorine, — I presume by the action of carbonic acid, — that it 

 does not contain two per cent, of it in any state, either of mix- 

 ture or combination. I have not particularly examined the so- 

 lutic^n formed by decomposing chloride of lime by means oi 

 carbonate of soda; but I find that it retains its bleaching power 

 after ebullition, and yields crystals by evaporation. 



Jn the last Number of the Phil. Mag. and Annals, an 

 account was given of a paper of Dr. Granville's, read before 

 the Royal Society, on the composition and action of the chlo- 

 ride of soda. According to Dr. Granville, tiie disinfecting 

 properties of chloride of soda are entirely dependent upon 

 Nau Scries. Vol. 1. No, 5. May 1827. 3 C the 



