A spring lifting instrument, shown right and wrong
Geared jack for raising a weight in 'correct' and 'false' versions and an exploded section, with a large timber engine below
The upper half-leaf works out a spring-and-gear instrument for lifting a weight, drawn twice: one version labelled 'correct' and another 'wrong,' with faces marked M and N that should carry a wheel to bind and cover 'the secret of the springs.' A lever below gives the first motion by rising and falling a single braccio, and an exploded section down the left, lettered A-A-A-N-B, breaks the instrument into its pieces to show how the spring at B engages the teeth N. The lower part of the sheet is filled by a large timber engine with a great curved arm, a central geared windlass and a free-standing ladder; the small companion half-leaf (148b) is recorded as blank. The Ambrosiana catalogue classifies additional geometric notes on the sheet.
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Lifting instrument: the 'correct' and 'wrong' versions
Two drawings compare a good and a faulty design for a weight-lifting instrument. The 'wrong' one is deliberately left uncased so its workings show; its faces M and N ought each to carry a wheel that binds and arms and covers 'the secret of the springs.'
Lever of the first motion
The lever that starts the mechanism need only sink by one braccio and rise the same amount to drive it.
Exploded section, lettered A-N-B
Down the left margin the instrument marked A is taken apart into many pieces to show its proportion; the smallest piece carries, at its base (B), the spring that enters the teeth (N) of the neighbouring piece.
Large timber engine with a bent arm
The lower half of the sheet is dominated by a big machine on a timber frame: a great curved arm bent over the frame, a central geared windlass with a ratchet, and a tall ladder standing alongside. No caption identifies it.