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much greater extent than one would expect, considering the 
attention and care which is bestowed by good firms on the 
manufacture of th ese articles. Lately I tested several samples 
of what was termed “ pure” carbonate of potash, and “ pure” 
carbonate of soda, and citric acid, which were specially 
purified for use in the preparation of aerated waters, and I 
found all to be contaminated with lead to a greater or less 
extent. The manufacturer of these samples was apprised 
of this fact, and in reply he admitted that they contained 
traces of lead, but said it was impossible to obtain these 
substances free from metallic contamination at anything like 
reasonable cost, and he was quite satisfied that the quantity 
was not objectionably large. To overcome this difficulty I 
had to advise the use of the ordinary carbonate of soda, 
made by Solvay’s ammonia process, as being almost as pure, 
and certainly much less likely to be injurious than the 
purified salt. I also advised that those salts which it is impos- 
sible to obtain free from lead should be dissolved in water, 
and filtered through or boiled with animal charcoal, which 
has the property of removing the lead from solution. It 
might here be noted that the use of charcoal filters diminishes 
very much the risk of lead poisoning, as the charcoal removes 
any trace of lead which the water might contain. 
It was first discovered and afterwards published by the 
late Dr. Crace-Oalvert and Mr. Richard Johnson in a joint 
paper, that pure lead is more easily acted on by sulphuric 
acid than lead containing a very small percentage of 
impurities such as antimony and copper, and these results 
have been repeatedly verified since. With a view to find 
the effect of pure water on comparatively pure lead and on 
lead to which I added f of a per cent of antimony, I 
melted some of the original lead and poured some out, 
which I rolled into a sheet. Antimony was added to the 
remainder, and the mixture poured out and rolled into 
a sheet as before; both sheets were cut to the same size and 
