Later he was chosen director of the university observatory, which was erected (1818-1821) under his superintendence.
Vallot built an observatory and shelter hut (14,31 2 ft.) on the Bosses du Dromadaire (north-west ridge of the mountain), and in 1893 T.
C. Janssen constructed an observatory just below the very summit.
Observations are made at a given height over level open ground near the observatory, and a comparison with the simultaneous results from the self-recording electrograph enables the records from the latter to be expressed as potential gradients in the open.
Luiz; (17) Annual Reports, Central Meteorological Observatory of Japan; (18) Observations made at the Mag.