alidades

The line, a1 a2, that joins these axes is parallel with that which joins the axes of the two telescopes; and the alidades are connected electrically with the telescopes by a system such that each alidade always moves parallel with the telescope that corresponds to it.

Scientific American Supplement, No. 363, December 16, 1882 Various

T T, that carries two alidades, a1v1, and a2v2, movable around their vertical axes, a1 and a2.

Scientific American Supplement, No. 363, December 16, 1882 Various

The alidades themselves are provided with a button which disengages the toothed sector from the endless screw, and permits of their being turned to a mark made on the table.

Scientific American Supplement, No. 363, December 16, 1882 Various

If, then, we know the ratio of a1, a2 to A1 A2, it will suffice to measure on one of the alidades the distance from its axis to the point of crossing in order to know the distance from the movable object to the axis of the corresponding telescope.

Scientific American Supplement, No. 363, December 16, 1882 Various

In order to obtain a parallelism between the motion of the alidades and that of the corresponding telescopes, the winch of each of the latter, while putting its instrument in motion, also sets in motion a Siemens double-T armature electromagnetic machine.

Scientific American Supplement, No. 363, December 16, 1882 Various

In this way there maybe had a powerful auxiliary in coast defence; for all the points at which torpedoes have been sunk may be marked on the chart, and, as soon as the operator at the table finds, by the motion of the alidades, that the ship under observation is directly over a torpedo, he will be able to fire the latter and blow the enemy up.

Scientific American Supplement, No. 363, December 16, 1882 Various

If the table, T T, be covered with a chart giving the space over which the ship is moving, so that a1 and a2 shall coincide with the points which A1 and A2 represent, the crossing of the threads of the alidades will permit of following on the chart all the ship's movements.

Scientific American Supplement, No. 363, December 16, 1882 Various

It follows from this that the small triangle that has for apices, a1 a2, and the crossing point of the two alidades will always be like the large triangle formed by the line that joins the telescopes and the two lines of vision.

Scientific American Supplement, No. 363, December 16, 1882 Various

Time must be allowed the men to make their stride scales and to paste or transfer them to their alidades.

Military Instructors Manual Oliver Schoonmaker