furnishing. To get the best results a belt wants to sag slightly as it
hugs the pulley closer, and will last much longer.

SOMETHING ABOUT SIGHT-FEED LUBRICATORS

All such lubricators feed oil through the drop-nipple by hydrostatic
pressure; that is, the water of condensation in the condenser and its
pipe being elevated above the oil magazine forces the oil out of the
latter by just so much pressure as the column of water is higher than
the exit or outlet of oil-nipple. The higher the column of water the
more positive will the oil feeds. As soon as the oil drop leaves the
nipple it ceases to be actuated by the hydrostatic pressure, and rises
through the water in the sight-glass merely by the difference of its
specific gravity, as compared with water and then passes off through the
ducts provided to the parts to be lubricated.

For stationary engines the double connection is preferable, and should
always be connected to the live steam pipe above the throttle. The
discharge arm should always be long enough (4 to 6 inches) to insure the
oil magazine and condenser from getting too hot, otherwise it will not
condense fast enough to give continuous feed of oil. For traction or
road engines the single connection is used. These can be connected to
live steam pipe or directly to steam chest.

In a general way it may be stated that certain precaution must be taken
to insure the satisfactory operation of all sight-feed lubricators. Use
only the best of oil, one gallon of which is worth five gallons of cheap
stuff and do far better service, as inferior grades not only clog the
lubricator but chokes the ducts and blurs the sight-glass, etc., and the
refuse of such oil will accumulate in the cylinder sufficiently to cause