Analysis of the Hot Springs at Bath. 345 



(V) Sulphuretted hydrogen water,— no precipitate or 

 change of colour; the water became very slightly turbid. 



(W) Prussiatc of potash. — no immediate effect: after 

 some weeks the water became slightly green. 



(X) Infusion of galls,— innnediately a peach-blossom red 

 colour, and very soon a precipitate which became dark purple 

 by exposure to the air. 



All the above effects are also produced after the water has 

 been cooled, excepting that the colour of tincture of tur- 

 meric is not then destroyed, and, under some circumstances, 

 no red colour occurs upon the addition of infusion of galls. 



(Y) A quantity of the water was evaporated to dryness, 

 and distilled water added to the residuum. Nitrate of lime 

 poured into the solution atlbrdcd a crystalline precipitate 

 in a few hours, indicating the presence of an alkaline sul- 

 phate. 



I shall now state the inferences to be deduced from these 

 experiments. 



Carbonic acid exists in this water (BE). A considerable 

 portion of it escapes at the high temperature at which the 

 water is obtained, its evolution occasioning the precipitation 

 of some substance which it held in solution (K). 



From Experiment (L) it is evident that no sulphuretted 

 hydrogen gas is present. 



As no alteration of colour is effected upon tincture of llt- 

 rnus by the carbonic acid (M), it is evident that acid is pre- 

 sent only insufficient quantity to dissolve the substance pre- 

 cipitated by its evolution. 



The destruction of the colour of tincture of turmeric (N) 

 is clearly occasioned by the gas during its passage through 

 the water (D). 



The effect produced in Experiment (O) is owing to the 

 formation of carbonate of lime, and the precipitation of 

 it aud of the substance previously dissolved by carbonic 

 acid (K). 



A part of the precipitate obtained by adding ammonia (P) 

 must have been similar to that of Experiment (K), and to a 

 portion of that of Experiment (O), produced in (P) and (O) 

 by combining the solvent carbonic acid instead of expelling 



it 



