Part letter from [Élie-François Wartmann], Lausanne, to Charles Wheatstone, 20 Conduit Street, London Table of hourly meteorological observations [p.1] made from 6.00am on 21 March 1842 to 6.00pm on 22 March 1842 [Spring equinox]. With columns for the hour, barometer, exterior thermometer and hygrometer readings, wind direction and cloud cover, with general remarks. Headed: 'Observations météorologiques horaires, faites à l'Equinox de Printemps 1842, dans le Cabinet de Physique de l'Académie de Lausanne'. Endorsed [p.2]: 'Observations Lausanne 1842'. Red wax seal with the initials 'EW'. 30 April 1842 [p.m.]