Analysis of the Hot Springs at Bath. 353 



former case ascertained. The experiments made with this 

 \\ ere as follow : 



[n) One ounce of a solution of red sulphate of iron, con- 

 taining .^.^\, ^,dih of a grain of oxide, was treated with infu- 

 sion of iralls. The usual indications of its action upon oxide 

 of iron were presented. 



(o) The addition of prussiate of potash to an equal quan- 

 tity of the solution immediately occasioned a blue co- 

 lour. 



[p) Infusion of galls was arlcled to one ounce of a dilute 

 solution of carbonate of lime containing -i-„-'g^dth of a grain 

 of the per -xiJc of ir&n. Slight indications of its action upon 

 the oxide were produced, but the colour was scarcely more 

 intense than that effected by To^oTnrdth of a grain of protox- 

 ide in similar circumstances : no effect whatever was pro- 

 duced by infusion of galls upon -nrJnrodth of a grain of per- 

 oxide in one ounce of solution of carbonate of lime. The 

 colour produced when carbonate of lime and infusion of 

 galls are added to the peroxide is red purple, similar to that 

 occasioned by their action upon the protoxide. 



{q) To one ounce of a solution of carbonate of lime, con- 

 taining, as in the last experiment, -J^-^dth of a grain of 

 peroxide of iron, prussiate of potash was added. Not the 

 slightest blue colour was produced. When carbonate of 

 lime was thus added to the solution of peroxide of iron, I 

 found that it was capable of preventing the action of prus- 

 siate of potash upon -^-i-o-th of a grain. 



From these experiments it is evident that carbonate of 

 lime possesses, in a very great degree, the power of in- 

 creasing the action of infusion of galls upon protoxide of 

 iron ; while, on the contrary, it diminishes its power in de- 

 tecting peroxide of iron ; and is, moreover, capable of pre- 

 venting the action of prussiate of potash. 



The application of these experiments to the circumstances 

 of the water in question is obvious. It has been shown that 

 it contains carbonate of Jime; and that the power of infusion 

 of galls to detect the oxide of iron it contains is completely 

 lost by the absorption of oxygen. The following experi- 



Vol. CI. No. 90. May 180G. Z ment 



