pound-condensing engine, has very little, if any, effect on the
economy of the engine. With the turbine, on the other hand, any increase
of vacuum, even up to the highest limits, increases the economy to a
very considerable extent and, moreover, the higher the vacuum the
greater will be the increase in the economy for a given addition to the
vacuum. Thus, raising the vacuum from 27 to 28 inches has a greater
effect than from 23 to 24 inches. For this reason the engineer will
readily perceive the great desirability of maintaining the vacuum at the
highest possible point consistent with the satisfactory and economical
operation of the condenser.

The exhaust pipe should always be carried downward to the condenser when
possible, to keep the water from backing up from the condenser into the
turbine. If the condenser must be located above the turbine, then the
pipe should be carried first downward and then upward in the U form, in
the manner of the familiar "entrainer," which will be found effectively
to prevent water getting back when the turbine is operating.

Condensers

As has been previously pointed out, the successful and satisfactory
operation of the turbine depends very largely on the condenser. With the
reciprocating engine, if the condenser will give 25 inches vacuum, it is
considered fairly good, and it is allowed to run along by itself until
the vacuum drops to somewhere below 20 inches, when it is completely
gone over, and in many cases practically rebuilt and the vacuum brought
back to the original 25 inches. It has been seen that this sort of
practice will never do in the case of the turbine condenser and, unless
the vacuum can be regularly maintained at 27 or 28 inches, the condenser
is not doing as well as it ought to do, or it is not of the proper type,
unless perhaps the temperature and the quantity of cooling water
available render a higher vacuum unattainable.

On account of the great purity of the condensed steam from the turbine
and its peculiar availability for boiler feed (there being no oil of any
kind mixed with it to injure the boilers), the surface condenser is very
desirable in connection with the turbine. It further recommends itself
by reason of the high vacuum obtainable.

Where a condenser system capable of the highest vacuum is installed,
the need of utilizing it to its utmost capacity can hardly be emphasized
too strongly. A high vacuum will, of course, mean special care and
attenti