Machine Studies: Pincers, Screw-Jack, Springald and Arches
Mechanical and structural sketches, with notes on pincer jaws and types of arch
The sheet is crowded with mechanical and structural studies: pincers or tongs, a screw-jack raising an arched frame, an inclined throwing-arm of the springald type, a spoked wheel, and a device the scholarly catalogue reads as one for generating a loud sound. A short note compares the jaws of a pair of pincers, saying a b is much weaker than c d. Along the left margin three brief captions distinguish kinds of masonry, an arch construction and a rubble wall. Sketches of ashlar blocks, a rough rubble wall and a well-head fill the lower left, and further untranscribed notes stand in the margins.
On this page
Pincer jaws a b compared with c d
A note beside the central figures compares the jaws of a pair of pincers. The jaw a b is judged much weaker than the jaw c d; the reasoning is begun ('First, because it is ...') but breaks off. The labels a b and c d mark the two jaws.
Types of arch and rubble wall
Three short captions along the left margin classify types of masonry beside the drawn walls. Two are noted as being of the arch kind, and one as a kind of rubble wall. They label the different wall sections sketched at the lower left.
Inclined springald-type throwing arm
At the upper part of the sheet an inclined throwing-arm mounted on a heavy timber frame is drawn, of the springald type, a large tension-powered engine for hurling projectiles. It is rendered in pen with hatched shading. No caption for it is transcribed.
Screw-jack lifting an arched frame
A screw-operated lifting device is drawn on the right, its threaded column raising a load while a standing figure indicates its scale and operation. Nearby are funnel-shaped hoppers and arched frames shown being hoisted. The apparatus is a screw-jack for raising heavy weights.