Rotational pulley, 1856.
© Science Museum / Science & Society Picture Library
Chromolithograph by E Wormser from 'Grands desins colories pour l'enseignement de la mecanique / composes sous la direction de M le General Morin ... et par les soins de M Tresca', by Arthur Jules Morin (1795-1880), published in Paris in 1856. Morin was profesor of mechanics at Metz and later director of the Conservatoire des Arts & Metiers at Paris. He wrote extensively on hydraulics, mechanics, and ballistics. The collected 30 plates were sold in a portfolio, but could also be bought as a series or separately, and were produced for the purpose of instructing the general public in the intricacies of mechanical engineering.