This is a large 6-inch theodolite by W. H. Harling, a name famous as a maker of drawing instruments. It has a 4-inch diameter compass on its horizontal plate.
Description
Item 3705
W. H. Harling 6” Transit Theodolite
This instrument is by W. H. Harling, a name famous as a maker of drawing instruments. It has a 4-inch diameter compass on its horizontal plate; on the silvered face of which is engraved:
‘W. H. Harling. / 40 Hatton Garden / LONDON’
W. H. Harling was at 40 Hatton Garden from 1877 to April 1889. He began in business as a mathematical instrument maker in 1851, the year of the Great Exhibition at Crystal Palace, when the British scientific instrument industry was at its zenith. Like many of the trade, he sold a wide range of goods including surveying, drawing and other mathematical instruments. The firm later specialized in drawing instruments and slide rules until 1964 when it merged with Blundell to become ‘Blundell and Harling’.
This is a 6-inch theodolite, referring to the diameter of the horizontal circle. This is larger than the standard 5-inch size in common use, the difference in physical size being considerably more than the mere numbers suggest; for a 6-inch circle has 44% more area than a 5-inch circle. Both circles are divided on silver with 20-minute graduations read by vernier to 20-seconds. It comes in a fitted mahogany case with a striding level, shown in place above the telescope in the main photo. Other accessories present are: the long erecting eyepiece (shown fitted to the instrument in the main photo); a 90-degree eyepiece for astronomical observations; and a burner with its supporting platform for illuminating the cross-hairs at night. Absent are two of the four interchangeable vernier magnifier lenses. Two of the bubble tubes are dry but intact.
The final picture is an extract from Harling's 1889 catalogue, with an illustration of what appears to be a very similar instrument, although without the accessories that this instrument comes with, and a less substantial form of tripod.
The handsome tripod, although evidencing one or two old repairs, is in good order. The case has military style flush handles and is in good order apart from the missing lock. In summary, this is a magnificent instrument, with a famous name rarely found on a theodolite, and which cannot fail to impress.
Approximate Dimensions
Instrument: 355 mm high or 405 mm with striding level, 375mm long over telescope.
Case: 370 x 365 x 210mm high
Tripod: 1.5m long
Approximate Weights
Instrument and case: 13 kg
Instrument, Case & Tripod: 20kg
Prices
POA - Instrument & Case
POA - Instrument, Case, & tripod
Freight is extra.
© Akrona Instruments
