Dr. Beck on the Chlorides of Soda, Lime, fyc. 269 



research to determine whether other gaseous bodies are sim- 

 ilarly affected in such solutions. 



Before leaving this part of the subject I shall notice one 

 other peculiarity in which the mere watery solution of chlo- 

 rine resembles those of the salts, which have been the subject 

 of experiment. 



It was ascertained by Mr. Faraday, that when a portion of 

 Labarraque's liquor was evaporated by exposure to air, crys- 

 tals were formed resembling those of carbonate of soda, 

 but which did not possess the slightest bleaching power. 



Upon exposing to air, a solution of sulphate of soda char- 

 ged with chlorine, for three days, the bottom of the vessel 

 was covered with crystals resembling this salt. But when 

 these crystals were dried between folds of thin paper and 

 rubbed down in water to near saturation, they had not the 

 least effect upon indigo or turmeric. 



A pint of rain water was charged with chlorine until it 

 bleached powerfully. Equal quantities of this watery solution 

 were put into two porcelain vessels of equal size ; the one 

 exposed to a temperature of about 25° F. the other to a tem- 

 perature of between 40° and 45°. At the end. of fourteen 

 hours a crust of ice, half an inch in thickness, was formed on 

 the surface of the former ; this was carefully detached and 

 dried as much as possible, by filtering paper at a low tem- 

 perature. It had a faint smell of chlorine, but when dissolv- 

 ed in water at 45° it exhibited no bleaching powers, while 

 the unfrozen water of this same vessel appeared to have lost 

 none of its effieiency upon indigo or turmeric, nor had the 

 solution from the other vessels, exposed at 45°, at all deterio- 

 rated. Portions of these different solutions were now added to 

 equal portions of solution of indigo, with papers of turmeric, 

 and set aside for two days, taking care to preserve an unifor- 

 mity of temperature throughout the whole progress of the 

 experiment. At the expiration of this time, the dissolved ice 

 had not in the least degree changed the color of the indigo, 

 but the turmeric paper was slightly reddened ; — the other so- 

 lutions were perfectly colorless. 



These experiments, as I conceive, warrant the conclusion, 

 that the process of free and perfect crystalization destroys 

 the bleaching powers of these substances, by the expulsion 

 of chlorine. Is it probable that any definite compound of 

 chlorine would be destroyed by this cause ? 



