271.—Feet and Inches Staff.—For building works, drainage, and some other cases, the staff is divided into feet and inches, and subdivided again into eighths or tenths of inches. This is most convenient when the work has to be carried out with 5 or 10 feet rods and the 2-feet rule. The intermediate inches between the feet are better marked 3, 6, 9 only than fully figured. For rough usage the author has made a solid 10-feet pine staff, well painted. This has a strong hinge in the centre, and is kept stiff when open by a strong open hook. It closes face to face in two parts, which keeps the face clean. This is important for dock and drainage works, where the staff holder's hands in many cases necessarily get dirty by climbing; otherwise it bears much more rough usage than the telescopic staff, and is much cheaper to make. Fig. 104.
Fig. 104.—Stanley's rough levelling staff.
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272.—Mining Staves.—For levelling in mines, large sewers, and other cases were there is no height for the ordinary staff, the Sopwith staff is made in its closed form commonly 2 feet 3 inches and 3 feet 3 inches only in length, to open out respectively 5 feet and 8 feet, or in some few instances even shorter than these dimensions. The mine staff is in every way, except its length, similar to the ordinary Sopwith, [art. 259].
Fig. 105.—Stanley's patented mine staff.
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273.—Stanley's Portable Staff.—The writer has made a portable staff in lengths of 18 inches, somewhat like a French folding rule. It may be formed of three, four, five, or six lengths, opening out respectively 4 feet 6 inches, 6 feet, 7 feet 6 inches, and 9 feet. The separate pieces are flat boards, slightly sunk on the face to prevent the divisions being scratched in opening and closing, but left solid at the joint ends. The boards are attached together with a kind of rivet at each joint. A strong spring at the end of each piece with a catch and notch keeps the length opened or closed with sufficient rigidity.[8] The entire length of the staff when closed in 20½ inches. The same kind of staff forms a very useful builder's or drainage staff, divided in this case in feet and inches; and it is conveniently portable for carrying abroad. Fig. 105—E shows back view, F front view, G cross section, A longitudinal section. The holding springs are shown at BB′B″.
274.—A portable mine staff designed by Mr. G. J. Jee,[9] is said to be a useful staff for colliery work. It is constructed in three lengths, sliding one into the other. The bottom length of three feet is graduated in the ordinary way. The top of this length has a band attached to it, painted to continue the lower division of the staff upwards. The other end of the band passes over a roller attached to the top division of the staff. The roller contains a spring which keeps a constant tension on the band. By extending the lengths of the staff and clamping them, the staff may be lengthened out any distance to 9 feet. The weight of the staff is 5 lbs.