Dr. Urc 0)1 Chloride of Lime. 13 



delusive. The truth of this conclusion will still further appear, 

 on reflecting that an uncertain portion of chlorine is condensed 

 in the water of the trough, and that most probably a little 

 euchlorine is formed at the period when the gaseous product 

 passes from chlorine to oxygen. Thus, of the 39.9 grains of 

 lime present in the chloride, 24.9 seem to have merely parted 

 with their clilorine, while the other 15 lost their oxygen, equi- 

 valent to 12f cubic inches, or 4.3 grains, and the remaining 

 10.7 of calcium, combined with 19.3 of chlorine to constitute 

 the 30 grains of ignited muriate of lime. But 19.3 grains of 

 chlorine form 25.3 cubic inches ; hence 51.8-r25.3 = 26.5 is 

 the volume of chlorine disengaged by the heat, to which, if we 

 add 12f cubic inches of oxygen, the sum 39.16 is the bulk of 

 gas that should have been received. The deficiency of 9.16 

 cubic inches is to be ascribed to absorption of chlorine (and 

 perhaps of euchlorine,) by the water of the pneumatic trough. 

 In the above case, about one-half of the total chlorine came 

 off in gas, and the other half combined with the basis of the 

 lime, to the exclusion of its oxygen. I have observed that the 

 proportion of chlorine to that of oxygen given ofF by heat, in- 

 creases, as one may naturally imagine, with the strength of the 

 bleaching-powder. When it is very weakly impregnated with 

 chlorine, as is the case with some commercial samples, then the 

 evolved gas consists in a great measure of oxygen. 



Before proceeding to describe the manufacture of oxymuriate 

 of lime on the great scale, the average condition of the product 

 in the market, and the most convenient means of ascertaining 

 its bleaching quality, I shall beg leave to make a few theore- 

 tical remarks on the state of chemical combination, between 

 the lime and the chlorine, in the above bleaching powder. We 

 have seen that the atomic hydrate of lime, with a slight pneu- 

 matic pressure, absorbed in the first experiment 33 parts of 

 chlorine to 35.5, = the prime equivalent of lime : in the second 

 experiment it absorbed, without pressure, 30.4 ; and in the third, 

 by the aid of 13 per cent, of more water in the hydrate, 35.2 of 

 chlorine. But if we add as much water to the lime as to con- 

 stitute a trihydrate, that is, for 100 parts of lime 95 of water, 



