The plan is economical, but in view of the danger
that the main might be flattened by the weight of heavy traction-engines
passing over the roads, or that it might settle into local dips from the
same cause or from the action of subterranean water, in which dips water
would be constantly condensing in cold weather, the use of lead for this
purpose cannot be recommended. Steam-barrel would be preferable to cast
pipe, because permanently sound joints are easier to make in the former,
and because it is not so brittle.
The fittings used for acetylene must have perfectly sound joints and
taps, for the same reasons that the service-pipes must be quite sound.
Common gas-fittings will not do, the joints, taps, ball-sockets, &c., are
not accurately enough ground to prevent leakage. They may in many cases
be improved by regrinding, but often the plug and barrel are so shallow
that it is almost impossible to ensure soundness. It is therefore better
to procure fittings having good taps and joints in the first instance;
the barrels should be long, fairly wide, and there should be no sensible
"play" between plug and barrel when adjusted so that the plug turns
easily when lightly lubricated.
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