(FIG. 4.)
With respect to the tube, it is mounted like the Alt-Azimuth, but
with the plane of the horizontal movement corresponding to the
latitude of the place of observation, and therefore following
objects with one screw movement is in reality a telescope with
equatorial motions. It need not be of heavier construction than the
Alt-Azimuth, and there is not the double weight of counterpoising,
&c. as in the equatorial, and when circles are not desired this will
be the most economical, handiest, and easily managed instrument, as
it partakes of the equatorial form or motions. The telescope tube is
well balanced, and the declination movement is easy and free, and
fitted with a clamp screw, so that when the instrument is turned on
an object that object can then be followed by an endless screw.
It can be made to suit any latitude, and by the addition of foot
screws on a level floor, can be got into suitable adjustments, and
if it has to be removed (for the stand is very little heavier than
an ordinary Alt-Azimuth), “guides” can be provided, so that it can
go very approximately into the exact place again when brought out
for use. They are made, when desired, with a revolving body and fine
screw-motion in declination.