This boxwood slide rule has a miniature
blackened and silvered brass prismatic
inclinometer fixed to one end of the stock.
The telescope is set approximately and then
adjusted with a fine motion screw. A graticule
in the eyepiece is marked with a number of
scales and is used in conjunction with the scales on the slide rule. The instrument was designed for
surveying, and the bubble and straight levels were used to level the instrument on the drawing board. The
rule is marked with various surveying scales: “Cosinus, Sinus, Cotang, Tang.,Nomb., Dist., Prod.,
Millim., Angle”. The slider is stamped “TAVERNIER-GRAVET RUE MAYET 19 PARIS”. The
graticule is also made by Tavernier-Gravet (the original makers of the Mannheim slide rule). There are
printed instructions under the slider marked “INSTRUCTIONS SUR LES CALCULS”. This instrument
was invented about 1870 by the French inspector of roads and bridges Luitenant-Colonel Charles Moyse
Goulier (1818-1891). Length of stock 14.75” (375mm). Diameter of circle 2” (50mm). Good condition
(some loss of silvering and the three screws affixed to the box are absent). French c.1875 (the example in
the Arts et Metiers Museum in Paris was acquired by them in 1878). Ticket Price £790.
A unique object. A completely unused and uncut
compass card dated “1791”and inscribed
“THOs. SMITH INVTr.” This is the only reference
to Thomas Smith that has come to light during the past
forty years. The card was printed from an engraved
copper plate and is 8” (203mm) in diameter; it is shown
here mounted behind a black bevelled-edge card.
In very good condition. English, 1791.
Ticket Price £790.
