00 Mr. Faraday'5 Experiments on the Nature of 



was a gradual reaction of the chlorine and alkali in the fluid 

 preparation, proceeding to a greater extent than in the evapo- 

 rated portion ; for chlorine, equal to five parts, was found by the 

 nitrate of silver to remain. Hence this preparation is one 

 which deteriorates even in the small space of forty-three days. 

 Whether the effect will proceed to any great extent, prolonged 

 experiments only can shew. 



17. From an experiment made upon larger quantities of the 

 Labarraque liquor, it would appear that the force of crystalliza- 

 tion alone is sufficient to exclude the chlorine. A quantity 

 was put into an evaporating basin, and left covered over with 

 paper from July 16th to August 28th. Being then examined, 

 a few large crystals were found covered over with a dense 

 solution ; the whole had the innocuous odour of Labarraque's 

 fluid, and the fluid the usual acrid, biting taste. The crystals 

 being separated, one of the largest and most perfect was chosen, 

 and being well wiped on the exterior, and pressed between folds 

 of bibulous paper, was rubbed down in water, so as to make a 

 saturated solution. This had no astringent taste like that of 

 Labarraque's fluid, or the mother-liquor, but one purely alka- 

 line ; and when applied to turmeric paper, reddened, but did 

 not bleach it. Equal portions of this saturated solution and 

 of the mother-liquor were then compared in bleaching power, 

 acid being added to the former to assist the effect : it was found, 

 notwithstanding that portions of mother-liquor must have 

 adhered to the crystal, that its solution had not ^th part the 

 power of the mother-liquor. This, in conjunction with the 

 other experiments, is a striking instance of the manner in which 

 the carbonate of soda acts, as a simple substance, with the 

 chlorine in the solution. The crystal itself had never been in 

 contact with the air : but whether it should be considered as 

 the excess of carbonate of soda only which crystallized ; or 

 whether it is essential to the formation of these crystals that 

 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 evaporaticm a 



