150 PHILOSOPHICAL TRANSACTIONS. [aNNO \7Q'2. 



mineral water, but that the latter will be destroyed, as the fixed air is developed 

 by gentle warmth. 



Chemical experiments. Examination of the Kilburn waters by reagent sub- 

 stances. — Exper. 1. The tincture of litmus is very little affected by the water 

 fresh from the spring, and not at all after having been boiled: which proves that 

 this water contains very little aerial acid. — Exper. 1. Paper stained with a decoc- 

 tion of logwood is somewhat changed, to rather a bluish hue, by fresh water ; 

 from this Mr. S. infers, that the water contains a little absorbent earth dissolved 

 in aerial acid. — Exper. 3. Paper stained with turmeric is not changed by this 

 water; which would happen if it contained any uncombined alkaline salt. — 

 Exper. A. On adding 42 drops of the purest concenti-ated vitriolic acid to 1 lb. 

 of the Kilburn water, it became perfectly clear, and some air was disengaged; 

 this air rendered lime-water turbid. — Experiment. A few drops of pure nitrous 

 acid were dropped into n tumbler full of the water; the smell of hepatic air was 

 diminished, and hardly any precipitate formed. From this experiment it becomes 

 probable, that the water contains no liver of sulphur, but only hepatic air; from 

 the appearances on addmg the vitriolic acid, may be inferred, that this water 

 contains little calcareous earth, and no terra ponderosa. 



Exper. 5. In order to ascertain whether the hepatic air really existed in the 

 water, or whether the appearances which made this probable might not arise from 

 the air of marshes, which will occasionally imitate the other, Mr. S. filled 3 

 quart bottles with distilled w ater, and nearly emptied them just over and almost 

 in contact with the spring. The air, which of course took the place of the 

 water he had emptied, was subjected to the following experiments, (a) A piece 

 of white arsenic being immersed in it, its surface soon became yellow, (^b) A 

 solution of lead being put into one of these bottles, the precipitate formed soon 

 became of a blackish brown colour, (c) A solution of silver being put into the 

 3d bottle, the precipitate formed was blackish. All these are proofs of the ex- 

 istence of the hepatic air. 



Exper. 6. On adding a few drops, both of the aqueous and spirituous infusion 

 of galls, to a glass of the fresh water, no change of colour took place; yet by 

 means of well saturated phlogisticated alkali some traces of iron were perceived. 

 — Exper. 7. A solution of soap in s[)irit of wine being dropped into the water, 

 was immediately decomposed by it. This proves it to contain neutral salts. — 

 Exper. 8. By adding some acid of su'gar both to the fresh and the boiled Kilburn 

 water, calcareous earth was precipitated; which shows that this water contains 

 aerated calcareous earth, and selenite. — Exper. g. By adding aerated volatile al- 

 kali, magnesia and calcareous earth were precipitated both from the tresh and 

 the boiled water. — Exper. 10. Caustic volatile alkali precipitated both magnesia 

 and calcareous earth from the fresh water; a proof of its containing these earths 



