BY J. BKOWNLIE HENDEKSON, F.I.C., F.C.S. 139 



from the pipe for further examination. I obtained the following 



results : — 



Grains per Gallon. 



Total solids . . 



Chlorine 



Ammonia 



Nitrogen as nitrate . . 



Zinc carbonate in solution in carbonic acid 



" The solvent action upon zinc of water containing dis- 

 solved oxygen and free carbonic acid is, as the above figures 

 show, considerable. As far as I know it has not been observed 

 before. 



" I confirmed the analysis by a simple experiment. Dis- 

 tilled water containing some fragments of pure zinc was exposed 

 for about half an hour to a stream of oxygen and carbonic 

 anhydride. The filtered liquid was found to contain much zinc 

 in solution, this zinc being readily precipitated as carbonate on 

 boiling. 



" It will be seen that the Peuderry water is very pure 

 The reduction of the nitrate to ammonia by the action of the 

 zinc is a noteworthy feature in the case." 



On page 107 of same volume is a reprint of Dr. Stevenson's 

 well-known article which seems to give a resume of what was 

 known of the subject up to that date and which is here rf pro- 

 duced : — 



" The experiments of Boutigny, Schaueffele, and Langonn6 

 have long since shown us that zinc dissolves in potable waters 

 at ordinary temperatures ; that distilled water and rain 

 water dissolve zinc more readily than hard waters, especially 

 those that are rich in chalk. They have shown, however, that 

 hard potable waters do not take up zinc to an appreciable extent, 

 for the zinc speedily becomes coated with an insoluble layer of 

 zinc hydrate (hydrated oxide), or, more commonly, of hydro- 

 carbonate (hydrated oxide and carbonate) ; but still a portion of 

 the metal remains suspended, whilst a smaller portion, perhaps, 

 passes into a state of true solution. Thus, all kinds of vessels 

 in domestic use, whether made of zinc or ' galvanised,' impart 

 to waters kept in, or allowed to pass through them, a certain 

 quantity of zinc. The quantity of zinc thus taken up may even 

 be sufficient to render the water opalescent, and unfit for drink- 

 ing purposes. 



