No: 189822 ( click here for the Bausch & Lomb history)
On the disk of the middle axle, there are two numbers. One is the pat no: 83934 and second is BT5449
Bausch & Lomb was founded in 1853 by two German immigrants, John Jacob Bausch and Henry C. Lomb in Rochester, New York. They started to produce monocles. During the American civil war they produced spectacles made from vulcanite rubber.
In 1876, the company began manufacturing microscopes. Later that year, the Bausch & Lomb Optical Company won a distinction at the Philadelphia Centennial Exposition. The company also produced photographic lenses (1883), spectacle lenses (1889), microtomes (1890), binoculars and telescopes (1893). From 1892 in cooperation with Zeiss in Germany, the company produced optical lenses. In this manner, at the end of the 19th century, the product range included eyeglasses, microscopes and binoculars, as well as projectors, camera lenses and camera diaphragms.
The further development of the firm was affected by political events. Because of the World Wars and the consequent need for optical instruments such as field glasses, target finders, camera lenses, binocular telescopes, searchlight mirrors, torpedo tube sights and periscopes, the product range could be considerably broadened. During this period, military products represented 70 % of total production. One of the best-known developments in this period was the world-famous Ray-Ban brand sunglasses, developed for pilots in 1926.
The most famous Marine model binocular is the Bausch & Lomb 7 x 50.
The Mk 28 mod. 0 binocular is the standard, basic design of several marks and mods of 7 x 50 prismatic binoculars. Mod.0 was made waterproof by adding a rubber gasket between the cover and the body, together with a channel of wax. A rubber gasket was also added between the objective mount and the objectivelock ring The eyelens and the objective lens are set in a wax seal.