103 
solution, it charred paper with facility and gave a copious 
white precipitate with chloride of Barium insoluble in Hy- 
drochloric acid, thus proving it to be free Sulphuric Acid 
which had acted - upon the copper. I then continued my 
investigation to find the source of that acid. I observed 
that the boilers on each side of the fireplace were supplied 
by the same water, (Manchester supply) passing along the 
same pipe. I collected a sample of that water from the tap 
used for filling the copper boiler, and took another from the 
iron boiler on the other side, these samples were evaporated 
down and tested, but found to contain neither free acid nor 
copper. I next looked for the acid as a result of the com- 
bustion of sulphur in the coal, but as both boilers were 
entirely separated from the fire by brick work and also 
covered in on the top, the products of combustion had no 
chance of finding their way into the boilers, and further had 
this been the cause I ought to have found free acid in the 
water of the iron boiler. 
On further enquiry, I was informed that after the boiler 
had been put in, it was well washed with water and after- 
wards had a solution of washing soda boiled in it and again 
washed well with clean water. After this treatment, water 
which was heated in it became highly contaminated with 
copper and free sulphuric acid. 
My experiments up to this time having offered no solution 
of the problem as to how the water became contaminated, I 
made enquiries respecting the galvanizing of such utensils, 
and found that the process followed was this : the inside of 
the vessel was “ pickled ” with sulphuric acid, then rubbed 
with sand to remove oxide, and washed, lastly heated up 
with chloride of ammonium and block tin rubbed over the 
surface. 
The only explanation which I can offer of this remarkable 
contamination is, that part of the sulphuric acid used for 
cleansing before galvanizing had been secreted in the joints 
