1835.] Bleaching Powder, 437 



evolved. I found the best proportion to be, to mix 100 grs. 

 of bleaching powder with one cubic inch of water, and then 

 to add the ammoniacal salt in a solid state. When the 

 bleaching powder is as strong as possible, 107 grs. of it are 

 capable of decomposing the ammonia in 100 grs. of nitrate 

 of ammonia. The azotic gas disengaged amounts to about 

 31*5 cubic inches. 



As it was suspected by some foreign chemists of emi- 

 nence, that the chlorine in bleaching powder is not in the 

 state of simple chlorine, but united with oxygen, so as to 

 form an acid, I was anxious to put this opinion to the 

 test of experiment, — the only way in which chemical theo- 

 ries can be verified. I shall here relate, as shortly as pos- 

 sible, the results which I obtained : The bleaching powder 

 which I used was recently made, and it. was of the strongest 

 and best kind, manufactured by Charles Tennant & Co., 

 Glasgow, the original contrivers, and still the most exten- 

 sive manufacturers of this article. 



My method of proceeding was this : Into a small Berlin 

 porcelain retort, (previously weighed), 200 grs. of the 

 bleaching powder were put. To the beak of this retort 

 was luted a glass tube, about 14 inches in length, and about 

 an inch in internal diameter. This tube was filled with 

 fragments of fused chloride of calcium, which were kept in 

 their places by small quantities of asbestus, inserted into 

 each end of the tube. To the extremity of this glass tube 

 another bent glass tube was luted, by means of a ribbon of 

 caoutchouc. This tube passed to the bottom of a Wolfe's 

 bottle containing a solution of nitrate of silver, which very 

 nearly filled it. From the other mouth of the Wolfe's bottle 

 a glass tube passed into a pneumatic trough, to collect any 

 gas which might be evolved during the experiment. Heat 

 was now applied to the belly of the porcelain retort which 

 contained the bleaching powder, and was gradually raised 

 till the retort was red hot, and it was kept in this state till 

 all emission of gas was at an end. The apparatus was then 

 allowed to cool, and the different parts of it were detached 

 from each other. 



The loss of weight sustained by the retort gave the whole 

 matter that had been driven off by the heat. The increase 

 of weight of the tube filled with chloride of calcium, gave 



