462 EMILE PLANTAMOUR. 



(which has since been transformed into a University) and Director of 

 the Observatory. In 1848 he accepted also the chair of Physical 

 Geography, and he retained all three positions until his health began 

 to fail him, a few months before his death. His publications chiefly 

 related to atmospheric electricity, observations of comets, and meteoro- 

 lo'j-ical observations made on the Great St. Bernard. Special refer- 

 ence should be made to the important investigations of the diurnal 

 oscillations of the soil undertaken by him by means of spirit-levels, 

 and of which accounts are given in the Comptes Rendiis for 1878 and 

 1879. Much of his time was devoted to meteorology, and his papers 

 in the Bibliotheque Universelle on the subject were numerous; he 

 was also one of the most active members of the Helvetic Scientific 

 Society for the observation of atmospheric phenomena. He devoted 

 attention to geodesy, and in 1861 became the representative of 

 Geneva on the Paris Geodetic Commission. He was also a useful 

 member of the International Geodetic Association, which met a few 

 years ao'o at Geneva. In connection with the Genevan Society of 

 Arts he oro^anized a watch and chronometer competition, which has 

 proved of great value to the staple industry of Geneva. Watches 

 and chronometers are sent to the Observatory and tested there, the 

 results being published, and prizes awarded to tlie best time-keepers. 

 Four years ago he added to the Observatory at his own expense a 

 refractor of ten inches' aperture, and he erected the building for its 

 reception. He was a man of fortune, and might have devoted his life 

 to social enjoyment and ease ; but he was deeply attached to science, 

 and preferred to retain his posts at the University, altiiough the 

 modest salary he received scarcely covered his exjjenses. 



Plantamour's early work on cometary astronomy must not be passed 

 over unnoticed. One of his most elaborate investigations was his 

 determination of definite elements of Mauvais's comet of 1844, wliich 

 was observed from July 7 in that year to the middle of March, 1845, 

 and therefore offered a favorable opportunity for the calculation of 

 the true form of orbit. Plantamour's lesult was a somewliat notable 

 one : after taking into account the effect of the attraction of the 

 planets during the comet's visibility, he concluded that at the passage 

 through perihelion in October, 1844, the comet was moving in an 

 elliptical orbit with a period of revolution of 102,050 ± 3,090 years. 

 In 1846 he made extensive calculations bearing upon the motion of 

 the two heads of Biela's comet, the I'esults of which will be found in 

 No. 584 of the Astronomische Nachrichten. He further discussed the 

 elements of what was called at the time " Galle's second comet," 1840, 



