RfePORT ON MIXEUAL AND THERMAL WATERS. 49 



hiixture of strontian and baryt, whereby a soluble salt is formed 

 with the former, and an insoluble one with the latter. 



The precipitated chromate of barytes must be heated to red- 

 ness before it is weighed. 



The common method of detecting lithia in mineral waters is Lithia. 

 to precipitate it by phosphoric acid, a little phosphate of soda 

 being first added to the solution, in order to make sure of the 

 whole of the phosphate of lithia being thrown down. 



Kastner* proposes as an improvement, that the solution 

 should be neutralized by sulphuric acid, and then reduced to 

 dryness. 



Alcohol will take up the sulphate of lithia without aflfecting 

 the other sulphates, and the solution on being evaporated, and 

 then redissolved in as small a quantity of water as possible, may 

 have its lithia thrown down, in combination with phosphoric acid, 

 by phosphate of soda. 



An elegant method of detecting nitric acid was proposed by Nitric Add. 

 Dr. WoUaston. It consisted in adding to the liquid a few drops 

 of muriatic acid, and a little gold leaf, which latter will be dis- 

 solved if nitric acid be present f- 



DbbereinerJ has lately suggested another method, which 

 enables us to determine also the amount of nitric acid, even 

 when in small quantities. 



He mixes the suspected liquid with an equal quantity of con- 

 centrated sulphuric acid, and introduces the mixture into a 

 graduated tube, placed over quicksilver. A slip of copper is 

 then added, and the mixture warmed. Sulphate of copper is 

 thus formed, and an amount of azote collected equivalent to that 

 of the nitric acid present. 



A more convenient plan of conducting the experiment would 

 seem to be, that of heating the suspected liquid in a glass tube, 

 containing a little metallic copper and sulphuric acid, and re- 

 ceiving the gas over mercury. 



I have already noticed the probability that ammonia has often Ammonia. 

 been overlooked in our analyses of mineral springs. To detect 

 it, sulphuric acid should first be added to the water, which may 

 then be concentrated, and evaporated in a water-bath, after 

 which the addition of quicklime will separate the ammonia, and 

 render it sensible both by its odour and alkaline reaction. 



The received method of estimating the amount of bromine. Bromine. 



* Archiv, vol. xvi. 



-f Becquerel has proposed an electro -chemical method of effecting the 

 same object founded on the same principle. Traite de I'Electricite, vol. iii. 

 p. 325. 



X Berzelius, Jahresberickf, 1832, p. 162. 

 VOL. V. 1836. B 



