SENSIBLE TESTS OF CERTAIN ACIDS AND AMMONIA. 36 i 



tected by its means ; but this test is greatly surpassed by Mild nitrate of 

 J i i i r\ mercury much 



the solution of mild nitrate of mercury prepared cold. Une bupe rior, 



part of muriatic acid of the specific gravity of 1-15, dilated 

 with 70000 parts of water, barely exhibits a slight ppaline 

 hue, when tested with nitrate of silver. Diluted with 

 80000 times its weight of water, it eludes the action of this 

 test, as well as of all others, except the mild nitrate of mer- 

 cury, which renders it very perceptibly turbid. Its sensi- Indicates 

 bility is so great indeed, that even T5 ^^^ of a grain of mu- T&eoa? 

 riatic acid at 1-15 is indicated by a slightly dull tint in the 

 water that contains this extremely small quantity. From 

 reflecting on the absolute insolubility, as it may be called, 

 of the mild muriate of mercury, I was led to experiments 

 concerning this reagent. 



It is at the same time the most sensible icst of ammonia. Detects 

 One part of this alkali, diluted with 30000 of water, is in- of ^^ 

 dicated by a slight blackish yellow tint, when a solution of 

 nitrate of mercury at a minimum of oxidation is added to it. 



Lime water, or barytes water, is generally considered as Acetate of lead 

 the most sensible test of carbonic acid. I have found, that test f carboni* 

 the acetate of lead surpasses both. I was led accidentally acid. 

 to make this observation. Some distilled water, which I 

 kept in a cellar not very deep under ground, where how- 

 ever there were no fermented liquors, was rendered very 

 sensibly turbid, by adding this solution. Kirwan has ac- 

 cused the acetite of lead of being a deceitful test, his solu- 

 tion, which had been kept a little time, being sometimes 

 rendered turbid by pure distilled water. But it is not de- Not deceitful, 

 ceitful ; the water in this case is not pure, it contains a lit- 

 tle carbonic acid. I prepared some distilled water free from 

 all carbonic acid. It was not rendered turbid either by 

 Jlimewater, or by the solution of acetite of lead. I passed 

 into it a few bubbles of carbonic acid, which acidulated the 

 water so slightly, that it neither reddened litmus paper, nor 

 tendered limewater turbid ; but the solution of acetite of 

 lead whitened it perceptibly. 



Acetate of lead is much less sensible to other acids. A Not s0 sen sible 

 solution of sulphuric acid at 1-85, diluted with 16000 parts 

 of water, which acts sensibly on litmus paper, is not ren- 

 dered turbid hj acetate of lead. Barytes water howeTer 



Vol. XVII. — Supplement. 2 B detects 



