… barometers, hygrometers and psychrometers, recording or not, and any combination of these instruments. …
Explanatory notes
… barometers, hygrometers and psychrometers, recording or not, and any combination of these instruments. … combined with a thermometer. Most of these instruments are known according to the use for which they are designed, for … pressure but also altitude; it should, however, be noted that the heading excludes altimeters (especially for …