m 
Mr Milne on Block-Tin Pipes . 
degree. After this trial, and the approbation of all the gas- 
engineers to whom I shewed it, I felt confidence in recommend- 
ing it to the public. 
I now proceeded to make tools for manufacturing tin-pipes of 
all sizes from J to 1 \ inch internal diameter, and have continued 
to use it ever since in preference to copper- pipe without a single 
complaint. 
The principal advantages I conceive block-tin pipe to possess 
over any other, are, First , Its being less liable to be acted upon 
by ga's, and from the nature of the metal not likely to oxidat e 
or corrode. Second , From its ductility it is easily bent to suit 
the different situations required ; and as the joinings are made 
with solder nearly of the same nature as the pipe itself, any blow 
or strain the pipe may receive at or near a joint can do little 
injury, as both the solder and the pipe will yield together, 
and never produce a leak, as copper-pipe, if put together 
with soft solder, is apt to do when subjected to the supposed 
strain. Copper-pipe is sometimes joined with screwed ferrules, 
which I think are more liable than solder to give way on getting 
a strain ; the surface being cut with the screw renders it weak, 
and therefore easily broken. Third , The facility of joining it is 
of considerable advantage, a considerable item in gas fittings 
being the men’s time occupied in laying the pipes. By the 
mode I use, (see Plate I. Fig. 10), any ordinary workman will 
make a perfect joint in less than two minutes, equally strong 
with the pipe itself, without a possibility of diminishing the in- 
ternal diameter a hair’s breadth, and not increasing the external 
diameter above ^th of an inch, which, if properly dressed off, 
at a distance of 5 or 6 feet, is not perceptible. 
From the construction of these joints, it occurred to me that 
a pipe might be joined and soldered while full of water. I tried 
the experiment in presence of a scientific gentleman, and com- 
pletely accomplished it under a pressure of a three foot column 
of water. 
If the beauty of the pipe were to add any thing to the price, 
most people would dispense with it ; but as it creates no addi- 
tional expence, its clean and polished appearance certainly gives 
it a preference, where pipes are exposed to view, as they are in 
many cases. 
