This drum microscope with rack and pinion focusing is signed on the outer tube: “J. & A. Molteni, 44 rue du Chateau d'Eau, Paris”. Joseph Antoine Balthazard Molteni, an Italian immigrant, set up an optical business in Paris in 1782. The firm, "Maison Molteni", continued on and was operated by various relatives throughout the 19th century. In 1863, the firm used the signature “J. & A. Molteni” and was operated by Jules and Alfred Molteni. One reference states the the firm was first located at the address shown on this microscope in 1872. This microscope is therefore a bit old fashioned for that time period.
In 1899, the firm was taken over by Radiguet and Massiot.