This Wild Heerbrugg T2 universal instrument was part of a large donation to my collection together with a 1969 Wild T2E theodolite, a 1950s Askania Tu400 theodolite, a 1951 Wild N2 level, a 1960s Jenoptik Koni 007 level, a 1960s Zeiss Opton Ni 2 level, a 1956 geodetic sextant, and various accessories.

The above mentioned group of instruments once was part of the set of instruments used by the field organisation TGTW of the Survey Department (Meetkundige Dienst, 'MD' in short) of Rijkswaterstaat (part of the Dutch Ministry of Infrastructure and the Environment, responsible for the design, construction, management and maintenance of the main infrastructure facilities in the Netherlands).

The department was closed in the early 2000s and in 2008 the instruments were donated to my collection.

The Wild T2 was first produced in 1926. The archetype Wild T2 in my collection was the third modification of the first model. The instrument shown here was the third model T2 produced, which was produced between 1956 and 1968, and dates from 1962. Two years later it would be followed by the Wild T2E in my collection.

This Wild T2 universal instrument is equipped with glass circles (90mm diameter horizontal and 70mm diameter vertical) and a optical reading mechanism. The T2 does not have a compensator for the vertical index, a coincidence vial is used instead (see figure 6). With 70mm diameter the vertical circle of this third model T2 is substantially larger than that of the archetype model T2, while the horizontal circle remained the same.

This T2 has centesimal circles divided down to 20c (0.20gon) intervals, can be read using a micrometer directly to 2cc and estimated to at least 1cc (see figure 11 and figure 12). The circles are illuminated by two distinctive rotating mirrors; one directly on the secondary axis and one at the base of the instrument (see figure 7 and figure 8).

Alternatively the circles can be illuminated by electric lights, but sadly enough the instrument came without them.

The first T2's were produced in 1926. Up to 1970 a total of 38,800 were made and many more thereafter.³ Here in the Netherlands the T2 has been the most popular instrument among surveyors for many decades and probably every surveyor educated here in the second half of the 20^th century has worked with it.

According to the Ahrend Prijscourant 22 of 1962 a "T2 in metalen stolp, met optisch lood ... elektrische verlichting zonder statief, 400g..." ("T2 in metal cover, with optical plumb ... electrical lighting without tripod, 400g") would have cost fl.3,630.-.⁴

This Wild T2 came complete with its steel container and lens cap. It is centesimally divided. The telescope has a magnification power of 30 times. The inverted field of view shows four stadia hairs with a multiplication factor of 100 (see figure 9).

Centring can be done using an optical plummet, which has a normal cross-hairs for the purpose (see figure 10).

Externally there are only two differences with the 1969 Wild T2E; the peep sight on the telescope (see figure 5, it is no longer featured on the later model) and the sliding (instead of turning) locking mechanism of the tribrach (see figure 3 and figure 4).

Internally the presentation of the coincidence reading method of the circles and the interval of the micrometer differ from the later model (see figure 11 and figure 12).