Theatre of Instruments and Machines

the northern ship is, so that no danger may happen to others, and so that they may be led to the port.

PROP. LIX.

Here at last we exhibit a type of new press and winch, consisting of three screws, which will be of use for the vintage, and for pressing cloths, likewise for printing geographical charts, and for stamping tapestries with leather or cloth placed underneath.

Declaration of the 59th figure.

No one fails to understand how great the force of the common screw is in presses, which here is more frequently multiplied, for the axle and the outer parts of the screws are three trispasts. The operator, however, applies force to the handle with a movement from the west, which he multiplies much more, as he draws to himself the radiating spokes facing the east with a long hook, when the force of that [spoke] and its weight are added to the forces of the movement.

PROP. LX.

It is scarcely credible how, by the principle of the balance-beam and a light motion contrary to nature, a vessel will be so arranged that it may propel itself in a calm sea, and accelerate its course in a slack wind, or moderate it in an excessive one; a matter truly worthy of a king's notice.

Declaration of the 60th figure.

The ship here is double-prowed so that this machine, which is to the south, may be placed in the middle of the prows; in it, at the head of the assembly, are two hinges by which, resting, it has free movement; in the last part is a circular rhombus, made almost like a cask, whose movement is free. Again, there is a pole from the end of which hang ropes, which appear in the larger ship and are wound around the windlass 1 p. 12 p. distant from the northern line, and 1 p. 7 p. from the eastern; and when these have been sufficiently wound, the rope is suddenly released by the workmen, whence the movement of the rhombus comes about. The aforementioned arm, at whose extremity the ropes are, with the rest of the assembly is a balance-beam, which appears here twice, namely in the ship leaning to the north and in the larger one, so that nothing may escape the reader. These are the things which I wished to say concerning the composition and use of these instruments: which I pray that candid readers may interpret favorably.

FINIS.