136 DOMESTIC WATER SUPPLY OF BRISBANE, ETC. 



vessel, before it commences to boil an iridescent film is observed 

 upon the surface, sometimes giving rise to the impression that 

 the water is 'greasy.' Such water should not be stored in 

 zinc or galvanised iron vessels, or passed through galvanised 

 iron pipes." 



" The River Pollution Commissioners mention that some 

 polluted shallow well waters not only act upon lead violently, 

 but continuously, and that several instances of poisoning from 

 the use of leaden pump pipes h«d come to their knowledge. 

 The one analysis given of such a water shows that it was far 

 purer than the average of shallow-well waters, but that the 

 temporary hardness was under 1". When a galvanised iron 

 pipe was substituted for the leaden one, the water, as might 

 have been expected from its composition, became charged with 

 zinc, and zinc poisoning followed the lead poisoning. The so- 

 called tin-lined lead pipes also yield lead to the water, inasmuch 

 as the tin in the process of lining becomes alloyed with the 

 lead. 



" As previously stated, water which acts upon lead will also- 

 attack the zinc coating of galvanised iron. A case of poisoning^ 

 from this cause recently came under my notice. The water 

 supply to a newly-erected country house was derived from a 

 spring aj?ising at the edge of a patch of Bagshot sand. The 

 water was piped from this spring to the house, a distance of 

 half a mile, through galvanised iron pipes. The only child^ 

 who, prior to the removal into the new house, had been perfectly 

 healthy, became a sufferer from obstinate constipation. At 

 length suspicion rested upon the water supply, probably because 

 an iridescent film always formed on its surface when exposed in 

 open vessels, or when heated in an open pan. (This film is- 

 very characteristic of the presence of zinc, and is often put down 

 to a trace of oil or grease.) Upon analysis I found that thfr 

 water contained about 8 grains of carbonate of zinc per gallon^ 

 When the water supply was changed, the constipation ceased. 

 Many months after I again examined the water, which had beea 

 allowed to flow freely through the pipe, in the hope that it would 

 speedily dissolve oft" the whole of the zinc ; but it still contained 

 too large a quantity to be considered safe for domestic use. Dr. 

 Heaton, in the Chemical Xfivs (22ud Feb., 188-4), gives an 

 analysis of a water from near Llanelly, which is carried for half 

 a mile through galvanised iron pipe. It was found to contain 

 over 6 grains of carbonate of zinc to the gallon. Unfortunately" 



