Fig. 79.—Stanley's quick setting-up level.
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240.—Quick setting-up Tribrach.—One objection has to be made to the tribrach over the four-screw system of adjustment, that the four-screw admits of greater inclination to the tripod, which is important in hilly countries. To remedy this defect the author designed a ball arrangement to the axis, which permits the level to be set 15° to the inclination of the tripod independently of the screw adjustment, so that the level, when the tripod is set at its best angle, may be brought immediately to nearly its final position. The arrangement is shown in the engraving Fig. 79. The axis carries a cup formed in the metal casting, which can be clamped down upon a ball-shaped recess formed upon the tribrach by means of a winged nut placed under it, the wings of which project between the tribrach screws. A very slight pressure is sufficient to firmly clamp the ball. This form of level is now very popular with civil engineers. With a point diaphragm and a tangent screw to the axis, not shown in the engraving, it is, in the author's opinion, the best practical level he has been able to design.
Fig. 80.—Stanley's Engineer's level.
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Since the last edition was written the reviser of this work introduced, in conjunction with Mr. Stanley, his new solid bodied engineer's level, which has practically revolutionized the form of dumpy level and has proved such a success that more of this form are now made than all other forms put together. In this level, Fig. 80, the centre, body of telescope, object end and bubble fitting are all combined in one piece of gun-metal, so that although of vastly greater strength and rigidity it does not weigh as much as the old form of tubular body with its collar and stage. This does away with many separate pieces which are usually soldered and screwed together. It thus forms the strongest and most compact level yet made, and with ordinary care it will last in perfect adjustment a lifetime. The pinion for focussing is fitted to the side of the cast body, instead of to a tube, thus greatly increasing its firmness. Its form is equally adapted to the four-screw levelling if desired, as shown on next page, Fig. 81, in which it will be seen the four-screw levelling is of much improved form, giving greater strength and far more wearing and bearing surface to the levelling screws.
