10 Dr. Henderson oil. the General Existence 



a pint, and the liquid separated from the solid matter which 

 had precipitated during the evaporation. 



The solid matter, inferred to be the sulphate of lime (with 

 silex) and iron, known to be the chief proportion of the solid 

 contents of the water, was not examined, as the inquiry re- 

 lated only to the easily soluble salts, which the liquid would 

 necessarily contain. The water on being further reduced in 

 a Wedgewood-ware basin, by cautious evaporation yielded 

 well-formed crystals of chloride of sodium, and a small por- 

 tion of a finely crystalline substance, which on examination 

 proved to be sulphate of lime. 



The taste of the concentrated water had hitherto been purely 

 saline, but when reduced to half an ounce, and separated from 

 the crystals which had formed, it was also bitter. 



The mother liquor was tested as follows : 



A. Oxalate of ammonia No change. 



B. Muriate of baryta... Dense precipitate insoluble in ni- 



tric acid. 



C. Carbonate of ammonia No change, but yielded a precipitate 



by boiling, and also by the ad- 

 dition of phosphate of soda. 



D. Muriate of platina.. Yellow precipitate. 



E. Solution of starch... No change, but a very decided vio- 



let precipitate on adding a few 

 drops of diluted sulphuric acid. 



F. Nitrate of silver Copious precipitate not xvh oily so- 



luble in pure ammonia. 



G. Chlorine gas No change. 



Experiment A. shows that all the lime had been removed. 



B. that sulphuric acid was present. 



C. indicated magnesia, 



D. potassa, 



E. and F. Iodine. 



G. showed that there was no bromine. 

 Comparative experiments with a solution of iodine upon the 

 starch test used, render it probable that the proportion of 

 iodine in the whole quantity of water evaporated was much less 

 than a grain. 



Jll. On the General Existence of Iodine in Spring Water. 



By R. Henderson, M.D. 



To the Editors of the Philosophical Magazine and Annals. 



Gentlemen, 



l\/rY attention has of late been directed to the statements of 



■'■'-'- Prof. Daubeny, respecting the existence of bromine and 



iodine in many of the mineral waters. I beg leave to observe 



that 



