Martin Brenner's, Pilot Balloon Resources
Scans and information on the Cooke, Troughton & Simms LTD. Model S25
Published specks for the Model S25 from a 1928 to 1930
catalog, Thanks to E. Ross of New Zealand..
Telescope - Fixed focus, bent axis type, 1.45 inch diameter 20 power i0 inch focal length. Transit axis held in screwed-down bearings.
Diaphragm (gradicule) Simple cross pattern in our interchangeable cell. 11 other styles were listed in the catalog as options.
Spirit Level - 40-45 secs to 2 mm., mounted on cover plate. (single level)
Leveling Base - Three Screw type.
Box - The instrument is packed in one piece in a mahogany box fitted with lock and key and a leather shoulder strap is provided.
Weights - Instrument only 13.0 pounds, Box and Accessories
Notes: The instrument appears to use friction wheels or tangent screws to drive the circles, but they are not specified as to having micrometer readouts. The catalog lists surveying instruments with micrometer readouts so is safe to assume that since this instrument is listed as having an index that it lacks micrometers.