Like the T2 universal theodolite and the travel theodolite, this triangulation theodolite also originated from the Institute of Geodesy and Photogrammetry. According to the order book, the Institute – which was still called the Geodetic Institute at the time – purchased it for 1725 in 1902. It is listed under entry number 20:

As can be seen in the source, it is listed here as a universal instrument. These are characterised by the fact that they can be used to measure angles both horizontally and vertically. The term “triangulation” refers to the type of surveying in which a triangle was defined by means of target points, such as mountain peaks, which was used as a basis for calculating its sides and angles. Known and existing target points and baselines were then used repeatedly for other measurements. ¹ This theodolite is characterised by two screw micrometers or screw microscopes, which were used to read the graduated circles.

It was manufactured by Hildebrand in Freiberg. Max Hildebrand (1839-1910) was a precision mechanic and made a name for himself in particular with the improvement of geodetic and astronomical instruments. He joined mechanical workshop August Lingke & Co. in Freiberg in 1873 and became a partner. He continued to run the company as Hildebrand and Schramm. Under his stewardship, this manufacture transformed into an industrial enterprise that achieved world fame. ²

The need for more precise surveying bases expanded at the beginning of the 20th century, and from 1903 a new national survey was made, based on the national survey of 1890. In the Alpine region, the large gaps left by the 1890 national survey had to be filled. This was done using theodolites with screw micrometers, i.e. very precise reading microscopes, made by Hildebrand Freiberg. This national survey constituted the first Swiss-wide network of fixed points, which formed the reference framework for surveying work in Switzerland for over 100 years. ³