288 Medicinal Mineral Water at Helwdn. 



The constituents of this water were exactly the same as 

 those in the other water. In addition, a small quantity of 

 silicic acid was found. The water likewise contained free 

 sulphuretted hydrogen. No iodine could be found in it. 



In the case of the two waters, it was impossible to perform 

 a quantitative analysis, owing to the small amount of water 

 at my disposal. 



3. TJie bottle with Sand. (C.) 



This specimen chiefly consisted of common siliceous sand, 

 mixed with a small quantity of sulphur, arising from the de- 

 composition of the sulphuretted hydrogen by contact with the 

 air, and lastly, of a very small quantity of sulphuret of iron, 

 which, together with some finely divided coloured sand, imparts 

 the dark colour to the water with which the sand is mixed. 



4. The Rock. 



This substance is soluble in hydrochloric acid, with evolu- 

 tion of carbonic acid. Only a very trifling proportion of 

 silica is left behind. The solution contains chiefly lime and 

 magnesia. The rock is therefore a dolomite limestone, in 

 which, moreover, traces of sulphate of lime, together with 

 common salt, are present. 



A quantitative analysis of the sand and of the rock would 

 not have afforded much interest. 



A. W. HOFMANN. 



For the purpose of obtaining a quantitative analysis of the 

 solid constituents of the water, I addressed a letter, in the 

 absence of Mr Murray from Cairo, to Alfred S. Walne, Esq., 

 Her Britannic Majesty's Consul at Cairo, requesting him to 

 send me a concentrated solution, by the evaporation of a con- 

 siderable quantity of the water. This he kindly undertook to 

 do. but the medical officer of the viceroy, to whom the task 

 was confided, unfortunately evaporated the water to dryness. 

 Mr Walne, however, sent me the residuum of the evaporation 

 of 6J lb. of the water, weighing 58J grammes. This I 

 placed for analysis in the hands of Mr James S. Brazier, who 

 had long worked under Dr Hofmann in the Royal College of 

 Chemistry, and on whose skill and accuracy in such analyses 



