pplied, and would probably be found preferable to any of the expedients at
present in use. In all spindle valves opened and shut rapidly, it is
advisable to have the lower surface conical, to take off the shock of the
water; and a large lift of the valve should be prevented, else much of the
water during the return stroke of the pump will flow out before the valve
shuts.

524. _Q._--At what part of the boiler is the feed water admitted?

_A._--The feed pipe of most locomotive engines enters the boiler near the
bottom and about the middle of its length. In Stephenson's engine the water
is let in at the smoke box end of the boiler, a little below the water
level; by this means the heat is more fully extracted from the escaping
smoke, but the arrangement is of questionable applicability to engines of
which the steam dome and steam pipe are at the smoke box end, as in that
case the entering cold water would condense the steam.

525. _Q._--How are the pipes connecting the tender and locomotive
constructed, so as to allow of play between the engine and tender without
leakage?

_A._--The pipes connecting the tender with the pumps should allow access to
the valves and free motion to the engine and tender. This end is attained
by the use of ball and socket joints; and, to allow some end play, one
piece of the pipe slides into the other like a telescope, and is kept tight
by means of a stuffing box. Any pipe joint between the engine and tender
must be made in this fashion.

526. _Q._--Have you any suggestion to make respecting the arrangement of
the feed pump?

_A._--It would be a material improvement if a feed pump was to be set in
the tender and worked by means of a small engine, such as that now used in
steam vessels for feeding the boilers. The present action of the feed pumps
of locomotives is precarious, as, if the valves leak in the slightest
degree, the steam or boiling water from the boiler will prevent the pumps
from drawing. It appears expedient, therefore, that at least one pump
should be far from the boiler and should be set among the feed water, so
that it will only have to force. If a pump was arranged in the manner
suggested, the boiler could still be fed regularly, though the locomotive
was standing still; but it would be prudent to have the existing pumps
still wrought in the usual way by the engine, in case of derangement of the
other, or in case the pump in the tender might freeze.

527. _Q._--Will you