… Surveying (including photogrammetrical surveying), hydrographic, oceanographic, hydrological, meteorological or …
Explanatory notes
… etc.), in mining, in military operations, etc. This group includes : (1) Optical or opto‑electronic … a collimator or sighting telescope), used to determine gradients and inclines, mining dials , graphometers, heliostats for trigonometrical survey, etc. …