1S27.] On Labarraque's Disinfecting Soda Liquid. 229 



chlorine should simultaneously be given off into the air ; or 

 what would take place, if the water were abstracted without 

 the evolution of chlorine, I have not determined. 



18. Notwithstanding the perfect manner in which the chlo- 

 rine may be thus separated by crystallization and slow evapo- 

 ration to dryness, yet it is certain that by quick evaporation a 

 substance apparently quite dry may be obtained, which yet 

 possesses strong bleaching power. In one experiment, where, 

 of two equal portions, one had been evaporated in the course 

 of twenty-four hours to dryness upon the warm part of a sand- 

 bath, it, when compared with the former, had not lost more 

 than one-third of its bleaching power. 



19. With the desire of knowing what effect carbonic acid 

 would have on Labarraque's fluid, and whether it possessed 

 in a greater or smaller degree the power of ordinary acids to 

 expel the chlorine, portions of the solution were put into two 

 Woulfe's bottles, and a current of carbonic acid gas passed 

 through them. The gas was obtained from sulphuric acid 

 and whitening in a soda-water apparatus, and was well washed 

 in water. The stream of gas brought away small portions of 

 chlorine with it, but they were not sensible to the smell, and 

 could only be detected by putting litmus paper into the cur- 

 rent. An immense quantity of gas, equal to nearly 1300 times 

 the volume of the fluid, was sent through ; but yet very little 

 chlorine was removed, and the bleaching powers of the fluid 

 were but little diminished, though it no longer appeared alka- 

 line to turmeric paper. Air was then passed through the solu- 

 tion in large quantity ; it also removed chlorine, but apparently 

 not quite so much as carbonic acid. 



20. One other experiment was made upon the degree in 

 which the carbonate of soda in Labarraque's liquor resisted 

 decomposition by the chlorine, even at high temperature. Two 

 equal portions of the fluid were taken, and one of them boiled 

 rapidly for fifteen minutes ; both were then acted upon by sul- 

 phuric acid, blowing and heat, as described (11), and the two 

 were then tested by nitrate of silver, to ascertain the quantity 

 of chlorine remaining : it was nearly three times as much in 

 the boiled as in the unboiled portion ; and by comparing this 

 with the results before obtained (11), it will be seen, that after 

 boiling for a quarter of an hour, not more than a twentieth 



