24 Dr. Ure on Chloride oj Lime. 



I found that thirty grains of the manganese, thus treated, 

 occasioned to the apparatus, a loss of weight in one experiment 

 of 17.8 grains chlorine, and in another of 17.5 grains. Hence 

 100 grains were equivalent to about 59 of chlorine. I found 

 afterwards, by an imperfect analysis, that 100 grains of the 

 same manganese contained 10 of siliceous matter, 4 of water» 

 and a very little iron, probably, in all, about 16 grains, leav- 

 ing 84 of oxide of manganese. Thus apparently 100 grains of 

 pure peroxide of manganese should yield 70 of chlorine with 

 muriatic acid ; but we shall presently see, by other and more 

 rigid methods, that 100 grains are equivalent to no less than 

 81.80 of chlorine. Is this difference to be ascribed to the 

 itative oxide of manganese, containing a portion of protoxide, 

 or to some other contamination of which I took no account ? I 

 shall endeavour to answer this question by future researches ; 

 be this as it may, we obtained above 59 grains of chlorine, 

 whose volume is 77^ cubic inches. Hence, 100 grains of such 

 manganese yielded 19.526 grain measures. M. Welter says, 

 that it required 61 grammes of his oxide of manganese to de- 

 velope 14 litres, or 14,000 gramme measures of chlorine, which 

 gives the proportion of 1 00 to 22.900. His manganese must 

 have been at this rate much better than mine. The pure perox- 

 ide yields from 100 grains, 27.090 grain measures. 



From both the sulphate and muriate of manganese, purified in 

 Mr. Hatchett's elegant method, I procured proto-carbonate, by 

 adding solution of crystals of soda. This carbonate was well 

 washed and dried in a vapour, bath at 190° F. The proportion 

 of carbonic acid which this salt contained was determined by 

 the loss of weight it suffered by solution in dilute sulphuric 

 acid, and also by collecting over mercury, the volume of acid 

 gas disengaged from it by a red heat. It was thus found that 

 100 grains contained 35,4 of carbonic acid. From another, 

 100 grains of the carbonate, I obtained, by distillation in a 

 glass retort, 7.3 grains of water, leaving of dry proto-carbonate 

 92.7 grains, which contained 35.4 carbonic acid, and 57.3 of 

 protoxide of manganese ; but 35.4 : 57.3 : : 2.75 : 4.42, a num- 

 ber, therefore, representmg the prime equivalent of protoxide 



