Fig. 376.
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772.—Hand Rods, although used more generally by building surveyors, are extremely useful also to the civil engineer and land surveyor for town work among buildings and in mines. They are made 5 feet in length, less generally 10 feet. The 5-feet are made of single blades of lancewood or of two jointed to fold. The 10-feet are always jointed and made much stouter than the 5-feet. The 5-feet are generally sold in pairs.
Fig. 377.—Ordinary 5-feet jointed rods—plan and section of joint.
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773.—Ordinary 5-feet Rods are divided to every 3 inches, with feet only stamped with numbers, as shown Fig. 377. Where the rod is jointed the best form of folding joint is shown in the figure in section and plan. The spring S is sunk into the face of the rod at the joint on one side, and springs into a groove (housing) in the other side so as to lock the joint when it is either open or closed. The most useful dimension for the rod is 1 inch by 1/6 inch. Rods are nearly always made of lancewood, but they are preferred dyed black for neatness by many surveyors. A pair of rods is usually carried in a cowhide case. They are also often carried in the stem of a walking-stick hollowed out for the purpose. The rod or rods in this case are made much lighter, generally ½ inch by 1/8 inch for a pair of rods, or 7/16 inch by 7/32 inch for a single rod. The single rod is to be preferred in this case for its extra strength.
774.—Fully Divided Rods.—The author has made rods for many years divided to single inches. These measure from both ends—one end direct as Fig. 378 and the other end reversed by turning the rod over as Fig. 379. By this plan the rod gives direct measurement in feet, inches, and parts from either end, and the division is always placed outwards against the work, so that measures may be taken from either end by turning the rod over sideways, without turning it end for end.