1961 Wild Heerbrugg N3 old style

The 1961 Wild Heerbrugg old style N3 level.
Figure 1: The 1961 Wild Heerbrugg old style N3 level.
For a new product development of my company I needed two Wild N3 levels. A geodetic instrument dealer here in the Netherlands had two them in stock; one from about 1962 and this one from 1961. Despite being the oldest of the two it is in an amazing brand new condition, due to the fact that it has only been used for educational and research purposes at the Delft University.

The instrument is of Swiss origin, from the same manufacturer as the NKII, NK01, NK10, N2 and NA2 in the collection. The N3 was the top model of Wild Heerbrugg and - compared to other uncompensated levels - still is unsurpassed in accuracy.

The N3 was originally developed by Wild in 1926 and modernised in 1940 (becoming the version shown here) and again in 1973, one of which is in my collection too and in design looks very similar to the Wild TC1 in my collection.1

The Wild Heerbrugg N3 from the other side.
Figure 2: The Wild Heerbrugg N3 from the other side.
Accuracy
The Wild N3 is equipped with a built-in parallel plate micrometer in front of the 42 times magnification power telescope. It is the most accurate level in my collection. Only with the new style Wild N3 levelling the line of sight would be slightly more accurate, but the overall levelling result not.

The settling accuracy of the vial is about 0.25" (0.03mm at 25 metres or 1.2mm at 1km). Readings can be done down to 0.1 millimetres, while estimating another decimal is possible. The instrument allows to level a 1km double run - using the parallel plate micrometer - with an accuracy of 0.2mm (1σ, 68%).2

The instrument
The instrument is in mint condition and came with a period Wild Heerbrugg tripod, model IVa. Although being the wrong model (it should have been a IIa),3 I was very pleased with it as it is the correct tripod for my Wild T3, while a model IIa was already in my collection.

Notes

[1]: See the Product Overview Levels of the Virtual Archive of Wild Heerbrugg
[2]: See the N3 section of the Virtual Archive of Wild Heerbrugg
[3]: See the tripod section of the Virtual Archive of Wild Heerbrugg

If you have any questions and/or remarks please let me know.

The old style Wild N3 with its container.
Figure 3: The old style Wild N3 with its container.
 
A close-up of the plan parallel plate of the old style Wild N3.
Figure 4: A close-up of the plan parallel plate of the old style Wild N3.

The Wild Heerbrugg N3 and NK10 compared.
Figure 5: The Wild Heerbrugg N3 and NK10 compared.
 
The old and new style Wild N3 compared.
Figure 6: The old and new style Wild N3 compared.

The oculars of the coincidence vial, micrometer, and telescope next to each other.
Figure 7: The oculars of the coincidence vial, micrometer, and telescope next to each other.
 
The serial number indicates it was made in 1961.
Figure 8: The serial number indicates it was made in 1961.

The circular vial of the Wild N3.
Figure 9: The circular vial of the Wild N3.
 
A view at the built in coincidence vial.
Figure 10: A view at the built in coincidence vial.

A look at the micrometer.
Figure 11: A look at the micrometer.
 
An inverted view through the telescope showing two stadia hairs and wedged cross-hairs.
Figure 12: An inverted view through the telescope showing two stadia hairs and wedged cross-hairs.

Surveyor's crosses Geodetic Sextants Theodolites Total Stations Levels Standards Tools Firms
20th c. hydrostatic level 19th c. water bottle level 19th c. Secrétan Egault 19th c. Tibaut Lenoir 1928 Carl Zeiss Nivellier I 1924 Carl Zeiss Nivellier II 1926 Wild NKII 1948 Wild N1 1951 Wild N2 1965 Wild NK01 1965 Wild NK10 1961 Wild N3 1970 Wild NK2 1977 Wild N3 1999 Wild NA2-GPM3 20th c. Cowley 1960s Jenoptik Koni 007 1960s Zeiss Opton Ni 2