Vintage Bausch & Lomb Microscope Illuminator & Ballast Transformer Set (Type 31-36-44) – USA, c. 1930-1940 An original and complete Bausch & Lomb microscope illumination system, manufactured in Rochester, New York, USA, between the 1930s and 1940s. This matching laboratory set consists of the articulated microscope illuminator together with its original Type 31-36-44 ballast transformer/resistor, making it an increasingly scarce survivor from the golden age of scientific instrumentation. Unlike many surviving examples assembled from mixed components, both the illuminator and transformer are original Bausch & Lomb pieces. The lamp features a heavy cast-metal construction with adjustable articulated arm, precision collector lens with blue anti-reflective coating and original cream-coloured adjustment handles. The matching transformer is housed in its distinctive perforated steel cylindrical casing for heat dissipation and retains its original specification plate. Bausch & Lomb was one of the world's leading manufacturers of scientific and optical equipment, supplying laboratories, universities and research institutes throughout the 20th century. Today these industrial instruments are highly appreciated by collectors of scientific antiques and enthusiasts of industrial design. The set includes the original heavy-duty power cable with bakelite inline ON/OFF switch ("Arrow H&H", Made in USA), period green bakelite European plug and original cloth-insulated cable connecting the transformer to the lamp. Specifications Manufacturer: Bausch & Lomb Optical Co., Rochester, N.Y., USA Period: approx. 1930-1940 Transformer: Type 31-36-44 Plate specifications: Line 115 Volts | Lamp 6.5 Volts | 2.75 Amps Approx. total weight: 2.75 kg Approx. microscope height (as shown): 37 cm Approx. base diameter: 10 cm Approx. transformer: 12 × 24 cm Condition Very good vintage condition with normal signs of age and laboratory use. The original finish, metalwork and optics are well preserved, and the lens remains clear. The transformer retains its original identification plate and decorative ventilated housing. The electrical condition is unknown and untested. The seller is not qualified to test or assess vintage electrical equipment. The cloth-insulated wiring shows age-related wear and fraying near the housing. The set is therefore offered strictly as a collectible/display item and is sold as-is. Any future use should only follow inspection, rewiring or conversion by a qualified professional. Please study the photographs carefully, as they form an integral part of the description.