18 Oil (he Rc-agents of the Muriatic, 6^c. Acids. 



be ahlc to cliscorer its first traces and to follow its successive? 

 increase. IJiiherto nitrate of sliver has generally been used* 

 This re-ajjent is-, without doubt, extremely sensible as to the 

 above acid. Kirwiin asserts that we iBav discover by this 

 means one part of the acid diluted in 103,333 parts of water. 

 But this re-agent is still far surpassed by the solution of 

 the mild nitrate of mercury prepared in the cold way. One 

 part of murialic acid, of 1150- in specific gravity, diluted 

 with 70,000 parts of water, is scarcely announced even by 

 a feeble opalization ; when diluted with 80,000 times ita 

 weight of water it eludes the actioi> of this test, as it does 

 all the others, e.Hccpt the mild nitrate of mercury,, wbicli- 

 last affects veiy sensibly the water thus feebly acidulated. 

 The sensil)ility of this re-agent is so great, that even 

 ■j^.-g-B-fl-dlh of a grain of muriatic acid at 1 150 is indicated 

 by a slight dull shade in the water which contains this al- 

 most inconceivably small (juantitv. Reflecting upon the 

 aln-vost absolute insolubility of the mild muriate of mercury,. 

 I was induced to make some experiments concerning this 

 r«-ag;ent. 



Jt is alsoi the mos-t sensible ageat for ammonia^. One part 

 of this latter s i.>bs tan ce diluted with 30,000 parts of water 

 is announced by a slight blackish yellow shade, upon adding 

 solution of nitrate of mercury at the minimum of oxidation. 

 >Linie water, or water of baryles, are generally regarded as 

 the most sensible re-agents for carbonic acid. I discovered", 

 however, that the solution of acetate of lead still surpasses 

 them. I was' aceidenfally led to this remark : — some distilled 

 vv'ater, v^hicll 1 had preserved in a deep cellar, where there 

 were no fermented liquor?, was very sensibly affected upon 

 adding (Ills solution. No oilier agent changed it. Kirwan 

 has asserted that the acciite of lead is a deceitful re-agent, 

 its solution, chiefly when a little old, being sometimes affected 

 ■with pure distilled wiiier. Bat it is not so fallacious, how- 

 ever, as he imagines, because distilled water always contains 

 a little carboni:; acid, is never pure. T prepared distilled 

 water exempt from a.!l carbonic acid. It was not affected 

 cither by lime water or by the solution of acetite of lead. 

 J poured sonic drops of carbonic acid into it. The water 



was 



