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A LUXURY TELESCOPE IN SHEFFIELD SILVER, English, c.1800, signed "Kings
Patent, Gilbert & Co., London." Opening from 14-1/4" to 46"
(36 -116 cm), the telescope itself has a tapered main tube black-enameled
with white floral and geometric decoration, three drawtubes, 2" (52
mm) apparently triplet achromatic objective, erecting eyepiece system,
and dust slide. The 18" tall table stand has a tripod base with folding
legs (which reverse for stowage), tapered central pillar, swiveling altazimuth
mount, and telescope clamp. Construction throughout is of heavy silver
over copper. Condition is fine and functional throughout, noting some
inevitable chipping to the enamel on the main tube. And just where fine
sharp outside edges and corners are exposed, the silver has worn through
to show the copper, giving a lovely rich contrast to the instrument. The
whole assembly fits in an old possibly original carrying case with brass
fittings.
Sheffield plating is a process invented c. 1740, whereby a sheet of silver
is fused to a thicker one of copper, and the laminate then rolled to thin
it out. A further sophistication was patented in 1782 by J.L. Martin (Benjamin
Martin¹s son), a process of drawing silver-plated copper telescope tubes
directly by machine. This all became obsolete in the mid-19th century,
with the advent of electroplating.
"Gilbert & Co." seems to have been a c. 1800 briefly held business
name used by variously interconnected Gilbert family makers of navigational
and optical instruments; Clifton records no less than six related Gilbert
makers (through their total working range of 1719 to 1845), plus the following
partnerships: W. & T. Gilbert; Gilbert and Gilkerson; Gilbert & Son; Gilbert
& Sons; Gilbert & Co.; Gilbert & Wright; Gilbert, Wright & Hooke; Gregory,
Gilbert & Co.; Gregory, Gilbert & Wright. Both Gabriel Wright and Henry
Gregory held royal patents for navigational instruments, but we have not
clearly identified this "Kings Patent". The present instrument
is a beautiful example of the Gilberts¹ speciality of luxury craftsmanship
of telescopes. (8025) $8950.
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