This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1883 Excerpt: ...work are now carefully examined, and all inequalities and defects made level with pine wedges. The screws being in position under every part of the structure, and brought up to a firm bearing, the operation of raising is commenced. The workmen are arranged in pairs in such manner as to be opposite each other on both sides of the wall; every mail has from twelve to fourteen screws to operate, and to ensure simultaneous motion, the foreman gives a signal, generally by whistle. Each man thereupon advances the screw under his control one-half revolution, and moves to the next, until all the screws under his charge are advanced an equal distance. This process is repeated, when the signal is given, and the building is gradually raised (Fig. 3) without injurious disturbance to the...