No. XCIV.
A little engine, portable in one's pocket, which placed to any door, without any noise, but on crack, openeth any door or gate.
NOTE.
The simple engine called a Jack, used for the purpose of raising great weights, with small manual exertion, appears to be admirably calculated for this purpose; and its even uniform motion is evidently described by the noble author.
Ramelli has also given a description of several very curious instruments for the same purpose. Vide Artificiose Machini, p. 255, &c.