95.2 x 20.4
Carved wood,
brass and iron
INDEX 1788 : B.VI.116
Vaginae duae basibus ligneis insidentes: per utramque excurrit hasta ferrea, quae ad varios altitudines ope ferreae cochleae insistitur, et in summo capite inflexo trochleam sustinet ex orichalco. Hae cum Vectibus simul adhibitae inserviunt ad Vectem secundi, et tertii generis explicandum.
Two sheathes seated on wooden bases, through each of which passes a spear of iron, supported at various heights with the assistance of an iron screw and at the curved point of the upper part supporting a brass pulley. These applied at the same time with the levers serve to explain the lever of the second and third kind.
Two pulley supports each consisting of a wooden base with a sheath mounted on it, into which a quadrangular iron bar can be fitted and fixed by means of a screw at different heights, and which terminates in a fixed pulley made of brass.
From Colégio dos Nobres, catalogue n.º 108.
Musschenbroeck, Peter van, Introductio ad Philosophiam Naturalem, Leiden, 1762, Tab. VI, Fig. 8.