89 
therefore be regarded as a thoroughly efficient protection 
against the action of water on lead, but the test was a severe 
O 
one, and there can be no doubt that tin-coated lead pipe is 
much better adapted for use in making communication with 
the water mains in large towns than the ordinary lead pipe, 
whilst the cost of producing this coating, I understand, 
amounts to only a few shillings per ton of pipe. To test their 
respective values I placed water containing a small propor- 
tion of nitrate of ammonia in two pipes of the same sizes, 
the one tinned inside, the other the ordinary lead pipe. 
After standing about three hours I tested the water from 
each, the one from the tinned lead pipe contained only a 
trace of lead, whilst that from the ordinary lead pipe con- 
tained a large proportion of lead in solution. Similar 
results were obtained by leaving Manchester water in the 
same pipes for 18 hours. 
In certain boroughs, I understand, such as Salford, Old- 
ham and Southport, this tinned lead pipe is the only kind 
allowed to be used for making communication with the 
main, whilst in Manchester and other places ordinary lead 
pipe is generally employed. I have lately observed that the 
lead pipes which have been in use in Manchester for many 
years contaminate water left in them over the night to a 
considerable extent, but after the water has been used for a 
short time during the day it is free from any appreciable 
trace of lead. 
I have also tested the water after remaining 18 hours in 
the lead pipes in communication with the main in Salford 
where the tinned pipes are employed, and although the water 
was slightly contaminated with lead, it contained much less 
than that found in the water which stood for the same length 
of time in the ordinary lead pipes of Manchester. 
It is a fact, which I have observed from my experience 
during the last few years, that aerated waters are contami- 
nated with lead much more often, and in many cases to a 
