i8l3.] On the Oxymmiate of Lime, If 



liquor was also 18i grains. From this experiment the total 

 quantity of lime in 100 grains of dry oxymuriate v/as 37 grains. 

 In the former it was 39 grains. 



The quantity of lime in the solution being thus found, it re- 

 mained to find the quantities of muriatic acid and oxy muriatic 

 acid, with which it was combined. The muriatic acid was de- 

 termined as follows. 



ExPER. Ill .—Two hundred grain measures of a solution of 

 the sp. gr. r034 were taken; to these a given quantity of mu- 

 riatic acid test was added, such as previous trials had shown was 

 more than sufficient to expel all the oxymuriatic acid from the 

 lime. The new compound was well agitated in a bottle, and 

 the oxymuriatic acid gas was blown away as long as any continued 

 to be given out. — ^The liquid solution was then tested, and found 

 to be acid, but not to destroy colour. Nitr-te of mercury was 

 then added, as long as any calomel was ti*rown down. The 

 calomel, w^hen dried, v/eighed 31 grains ; one ninth of this 

 was muriatic acid = 3*44 grains ; from this deducting 

 the quantity added to the liquid 2' 14 grains 5 



there remain 1*3 grains of muriatic acid pre- 

 viously in combination with the Hme. Now we have seen that 

 the lime in 200 measures of liquid was 3*7 grains, which 

 would require 3*5 grains of muriatic acid ; it had previously only 

 1'3 grains ; therefore the lime in combination with oxymuriatic 

 acid must have been so much as would require 2*2 grains of 

 muriatic acid to saturate it. Hence it appears that nearly i of 

 the lime in the solution was engaged by muriatic acid, and the 

 remaining f by oxymuriatic acid. But the quantity of this last 

 was still undetermined. 



The usual way of comparing the values of any two bleaching 

 liquids, has been, I believe, to find how much of any given 

 coloured liquid a given portion of tlie acid liquor would saturate.^ 

 The experiment serves well for the purpose of comparison ; but 

 it does not inform us of the precise quantity, either of volume or 

 weight, of the acid gas which the liquor contains. We might 

 expel the acid gas from a given weight, either of the dry or 

 liquid oxymuriate, by means of an acid, in a graduated tube, 

 over mercury or water; but unfortunately both these liquids act 

 upon the acid: no doubt the analysis might be accomplished 

 this way ; but it would require an apparatus expressly for the 

 purpose. I have succeeded however another way in discovering 

 a very excellent test of the quantity of oxymuriatic acid in any 

 compound. This test is a solution of green sulphate of iron.-— 

 As soon as green sulphate of iron comes in contact with oxy- 

 muriatic acid solutions, the black oxide is converted into red, at 

 the expense of the oxygen of the oxymuriatic acid ; if the sul" 



Vol. L L B 



