102 
“ On the Presence of Sulphate of Copper in Water heated 
in Tinned Copper Boilers,” by William Thomson, RC.S. 
A few weeks ago I was consulted with regard to some 
water which was taken from a copper boiler in a kitchen 
range, which led me to investigate the case, and, as the 
results seem to be of vital importance to many, I venture 
to bring them before your notice. 
The range referred to belonged to a large chapel in Man- 
chester, and was employed for culinary purposes in connec- 
tion with various meetings of the congregation, &c. It was 
originally formed of two iron boilers, each capable of holding 
from thirty to forty gallons, with a fireplace between. One 
of these boilers was cracked, through cold water having 
been carelessly thrown on the iron after it had been allowed 
to become nearly red hot. To repair this defect a copper 
boiler coated with tin was fitted into the cracked iron one. 
I was informed that this boiler together with the iron one 
on the other side of the range had been employed for heat- 
ing water for tea making at one or more meetings, and that 
some persons complained of feeling ill after tea. Some of 
the hot water from this boiler was afterwards employed for 
washing, and as it broke up the soap like hard water and 
threw to the top a scum which had a bluish colour, suspicion 
was thrown on it and a sample of the water brought to me 
for examination. It contained some matter in suspension 
of a dark colour, which soon subsided and left the water 
clear. Presuming that if copper were present it would be 
in suspension and not in solution, I examined the sediment 
but found it to be free from that metal. I then filtered and 
examined the clear water. 
It contained a large proportion of copper in solution, and 
gave a distinctly acid reaction to blue litmus paper. I 
evaporated the water down to a very small bulk and ex- 
tracted the free acid with absolute alcohol, eliminated the 
alcohol used, and got it in a concentrated form in a water 
