The T12 is a pocket theodolite with a canister no larger than a small thermos flask. Only about 1000 of these were produced. The horizontal scale is direct reading and very similar to those mounted on the period similar NK10 tilting levels. As an instrument it is therefore not very good; the next model in line, the T0, is a little larger but much better. Even a regular tilting level with horizontal scale will produce about the same accuracy (at a slighly larger size). And as to size, the B3 is smaller and probably just about as good for the jobs this instrument was used for (rough alignments).

What is special is that everything on this instrument is reduced in size. The instrument itself, but also the tribach is like the regular one but much smaller. The tripod is a copy of the leveling tripods of its day but about 2/3 the size making it much easier to take along (see the picture where it is shown next to other period triopds for 'regular' levels). The thread on instrument and tripod is actually standard 5/8" thread allowing the instrument to be set up on a full scale tripod (which needs to have a small head for the instrument not to fall through...) The tripod even reaches as decent height and as a result of the ocular being on the top does not even cost you your back. The vertical range is limited and is achieved by tilting a prism.

The instrument is in good shape and was originally sold by 'A van Hopplynus De Cock, Bruxelles' and 'Concessionaire exclusif pour Belgique et Congo' indicating its Belgian origin. The firm transformed in the 1957 into van Hopplynus and the in the 1960s into van Hopplynus Instruments SA untill the activities were taken over in 2007 by Leica Microsystems NV. The company still seems to exist but is now into real estate as part of Burco.

Maybe it was purchased for expeditions into Africa as instrument easy to take along. It has seen use as the tripod has one shorter leg, probably because the original leg has broken off. It is skillfully repaired but becomes obvious at closer inspection. It is lacking a plumb bob and neither is one available with the tripod as I bought them.

Apart from that as my wife would say "a cute little instrument".

More information / other collections:

Virtual Archive

Bennett

Leica microsystems