A very large two-part, 3” tapered single draw telescope with mahogany barrel signed on the draw tube J. Gilbert, Ludgate Street, London circa 1778. The telescope has a typical bulbus eye piece retaining the original dark slide. The draw tube has the eyepiece at one end and there are five other lens elements in the tube. The draw tube screws apart at the point where each of the lenses is set so they can be cleaned. At the center is a 2-part heavy brass threaded fitting allowing the telescope to tread apart into 2 more manageable sized parts. The objective lens is held within a round brass fitting at the end of the scope and has no lens cap. The telescope measures 3 inches in diameter at the front lens end and 3 inches at the eyepiece end.
Dimensions:
Length of telescope 75 inches. Section with front lens 36 ¾ inches, Section with eyepiece 38 ¼ inches,
Draw tube 17 ¾ inches, width of brass joining threaded joining bands 2 inches.
Condition: The telescope is extremely well preserved and is in its original untouched condition. All the brass parts have original lacquer. The wood barrel has a beautiful red mahogany color and is almost flawless.
Note: This is the longest 18th century telescope we have examined.
Reference: “Directory of British Scientific Instrument Makers 1550-1851, by Gloria Clifton, Published by The National Maritime Museum and Antiques Collectors Club, 1997, page 212.
J. Gilbert (3) was active between 1771-1780 at the 33 Ludgate London address. He apprenticed with his father John Gilbert (2) (1752-1791) and his father John Gilbert (1) worked between 1719-1749. The were highly recognized as scientific instrument and telescope maker in London for 3 generations.
Note: This is the longest 18th century telescope we have examined. John Gilbert (III) fallowing his father John (ll )succeeded the business of Joseph Linnell, a business that was originally founded by the great James Ayscough. William eventually succeeded to his Father’s business around 1776 after receiving his freedom from the Dollonds and continued to trade solely under the Gilbert name until his death in 1791.
