"No part of the equatorial mounting is shown in the figure, as it resembles every respect that usual Fraunhofer mounting. An adapted h is fixed on a telescope-tube, made of wood, in Fraunhofer's usual fashion. To this adapter is attached a flat circular flange h. The slides carrying the segments of the divided object-glass are mounted on a plate, which is fitted and ground to rotate smoothly on the flange h. Rotation is communicated by a pinion, turned by the handle c, which works in teeth cut on the edge of the flange h. The counterpoise w balances the head about its axis of rotation. The slides are moved by the screws a and b the divided heads of which serve to measure the separation of the segments. These screws are turned from the eye-end by bevelled wheels and pinions, the latter connected with the handles a', b'." —The Encyclopedia Britannica, 1903

Heliometer

"No part of the equatorial mounting is shown in the figure, as it resembles every respect that usual…