hen the gas has been several times subjected to the
washing process, it passes off by the pipe, K. Fresh cold water is
supplied to the vessel by the pipe, L; and M is the outlet for the
tar.--_Journal of Gas Lighting_.

* * * * *

THE WIND MILL.

[Footnote: A paper read before the Engineers' Club of St. Louis, 1884.]

By JAMES W. HILL.

In the history of the world the utilization of the wind as a motive
power antedates the use of both water and steam for the same purpose.

The advent of steam caused a cessation in the progress of wind power,
and it was comparatively neglected for many years. But more recently
attention has been again drawn to it, with the result of developing
improvements, so that it is now utilized in many ways.

The need in the West of a motive power where water power is rare and
fuel expensive has done much to develop and perfect wind mills.

Wind mills, as at present constructed in this country, are of recent
date.

The mill known as the "Eclipse" was the first mill of its class built.
It is known as the "solid-wheel, self-regulating pattern," and was
invented about seventeen years ago. The wind wheel is of the rosette
type, built without any joints, which gives it the name "solid wheel,"
in contradistinction to wheels made with loose sections or fans hinged
to the arms or spokes, and known as "section wheel mills."

The regulation of the Eclipse mill is accomplished by the use of a small
adjustable side vane, flexible or hinged rudder vane, and weighted
lever, as shown in Plate 1 (on the larger sizes of mills iron balls
attached to a chain are used in place of the weighted lever). The side
vane and weight on lever being adjustable, can be set to run the mill at
any desired speed.

Now you will observe from the model that the action of the governing
mechanism is automatic. As the velocity of the wind increases, the
pressure on the side vane tends to carry the wind wheel around edgewise
to the wind and parallel to the rudder vane, thereby changing the angle
and reducing the area exposed to the wind; at the same time the lever,
with adjustable weight attached, swings from a vertical toward a
horizontal position, the resistance increasing as it moves toward the
latter position. This acts as a counterbalance of varying resistance
against the pressure of the wind on the side vane, and holds the mill at
an angle to the plane of the wind, insuring thereby