A theodolite is used to measure angles, for example in engineering, architecture or surveying. This theodolite is a travel theodolite dating from 1899. Due to its small size and low weight, it was well suited for use on excursions.
ETH acquired this theodolite in 1899. It was later transferred to the Geodetic Institute, the present-day Institute of Geodesy and Photogrammetry.
Billwiller & Kradolfer
This travel theodolite was manufactured by Billwiller & Kradolfer. This company operated under this name from 1898 to 1903 and was based at Clausiusstrasse 38 and 4, very close to the Polytechnic (present-day ETH).
Billwiller & Kradolfer was a technical mail-order business specialising in the sale of surveying equipment. It also offered the full spectrum of schoolroom furnishings, as shown by the following advertisements dating from the period between 1898 and 1901. For example, the company had a representation of instruments from Kern & Co, Aarau.
The proximity to the Polytechnic and the representation of the Kern Aarau company was certainly highly advantageous to the mail-order company, since the Institute of Geodesy and Photogrammetry bought most of its surveying instruments from the two Swiss manufacturers Kern Aarau and Wild Heerbrugg. The Institute’s staff may well have examined and tried out the Kern theodolites right away in the mail-order shop at the Polytechnic.
Apparently, Billwiller & Kradolfer also manufactured some instruments themselves, such as this travel theodolite. The company praised the theodolite in an article in Illustrierte schweizerische Handwerker-Zeitung [Illustrated Swiss Craftsman’s Newspaper] as follows:
“This theodolite is primarily used for smaller angle measurements, checking or preliminary work, for use on journeys as well as all purposes which do not seem to require the use of larger instruments.”
We have 3D-digitised this theodolite because it is different from the other theodolites of the Institute of Geodesy and Photogrammetry. It is a very simple, small and unpretentious instrument and was produced by a little-known manufacturer. The theodolite is covered in white paint splatters, which become even more visible through the 3D digitisation. They were hardly noticeable on the original object. These traces of use indicate that it probably was not utilised in teaching and research, but may have been operated during the construction of a building? Perhaps even in the construction of an ETH building? As is so often the case with historical objects, we are in the dark as regards the context of its use and much can only be assumed.
Photogrammetry and modelling
The glass of the tube vial and the circular vial were created manually, as was the animation. The rest of the theodolite could be captured relatively well using photogrammetry, there were only a few reflections that disturbed the images.