The military level (fig. 11-26) is a semi-precise level designed for a more precise work than the engineers level. The telescope is a 30-power, 10-in.-long, interior-focusing type with an inverting eyepiece and an enclosed fixed reticle. The reticle is mounted internally and cannot be adjusted as in other instruments. It contains cross wires and a set of stadia hairs. The objective is focused by an internal field lens through a rack and pinion, controlled by a knob on the upper right-hand side of the telescope. The telescope and level vial can be tilted through a small angle in the vertical plane to make the line of sight exactly horizontal just before the rod reading is made.

The tilting is done by a screw with a graduated drum located below the telescope eyepiece. A cam is provided to raise the telescope off of the tilting device and to hold it firmly when the instrument is being moved and during the preliminary

Figure 11-26.-A military level.

leveling. An eyepiece, located to the left of the telescope, is used for viewing the bubble through the prism system that brings both ends of the bubble (fig. 11-13) into coincidence.

The level vial is located directly under the telescope, but to the left and below, directly in line with the capstan screws under the bubble-viewing eyepiece. The level vials sensitivity is given as 30 sec per 2-mm spacing. A circular bubble that is viewed through a 45⁰ mirror is provided for the first approximate leveling before the long level vial is used. For night work, battery-powered electric illumination lights the long bubble, the reticle, and the circular level. The clamping screw and the horizontal motion tangent screw are located on the right-hand side; the former near the spindle and the latter below the objective lens. The instrument has a three-screw leveling head. The tripod for this level has a non-extension leg to add rigidity and stability to the setup.