… floating instruments, thermometers, pyrometers, barometers, hygrometers and psychrometers, recording or not, and any …
Explanatory notes
… floating instruments, thermometers, pyrometers, barometers, hygrometers and psychrometers, recording or not, and any … thermographs record temperature (see Part (B) above). (D) HYGROMETERS AND HYGROGRAPHS These are used to determine the … the air or other gases. The main types are : (1) Chemical hygrometers , based on absorption of moisture by chemical …