The very first instruments showing the ideas of Heinrich Wild were a series of three levels that were produced during his years at Carl Zeiss Jena. These were the Nivellier I, II, and III. It was after production of these levels started that his designs made their way to the Carl Zeiss RThII and ThI theodolites.

The Nivellier II is a reversion level, which means that the whole telescope and attached vial can rotate around the telescope axis. In this way any misalignment between them will be cancelled out when observing in two faces.

The instrument reflects the following ideas of Heinrich Wild:

• The anallactic telescope of constant length with internal focusing;
• Device for centring the bubble by making apparent coincidence of its two ends as viewed in a prism;
• Cylindrical steel main axis;
• Dust-tight arrangement for foot screws.

The 285 millimetres long telescope gives an inverted view and has stadia hairs with a 100 times stadia constant. The magnification is 28 times with an aperture of 35 millimetres. Attached to the telescope is the main vial (see figure 2). Being a reversion level this vial can be turned over to the other side, allowing to eliminate any alignment errors between vial and telescope (see figure 4 and figure 5).

The vial of the Nivellier II has an accuracy of 15" per 2mm run. As the vial is of the coincidence type it should be no problem levelling it with an accuracy of 1" or better (0.1mm at 25 metres distance), which makes it (not coincidentally) about as accurate as the first level Wild produced in his own firm, the Wild Heerbrugg N2.

The length of this early 'modern' level does not differ much from period 'old fashioned' levels as the Secrétan Egault level or the J.-B. Tibaut Desimpelaere Lenoir level (see figure 8). It was not until Heinrich Wild started his own company that the dimensions of levelling instruments really started to reduce (see figure 8).

Based on the serial number (see figure 3) the instrument was made in 1924, but sadly enough the original user is not known.¹ The previous owner bought it in Latvia (in the city of Riga) at an antiques fair. However, as can be seen on figure 3 the telescope is signed "Gebr. Wichmann mbH., Berlin", a well known re-seller of geodetic instruments, similar to the Dutch firm Ahrend. Wichmann was founded in 1873, still exists and still sells geodetic instruments.

Despite its age the instrument came remarkably complete to the collection in 2013. Not only the box survived, but so did almost all the tools and accessories in it (see figure 10). In order to fit the box the instrument has to be severed from its tribrach (see figure 9).

The lid of the box contains two autographs, most likely of previous owners (see figure 12 and figure 13). Thanks to three fixtures on the back side the box can be converted to a rucksack (see figure 11).

[1]: With thanks to Dr. Wolfgang Wimmer and Ms. Dominique Schmied of the Zeiss Archives