MEMOIR OF PELTIER. 167 



covered tlie true canse of the electricity of vapors, (February 8, communication 

 to the Academy of Science.) This same year he procured a barometer, and six 

 months had not passed liefore he was able to comprehend the true cause of the 

 oscillations of this instrument, placing- in fact before the academy, April 25, 1842, 

 a sealed package containing the resume of his researches into the causes which 

 vary the barometrical pressure. At the same time that Peltier made by his obser- 

 vations so important a discovery, he published, in volume 4 of the third series of 

 the Annals, his great work on the cause of the electrical phenomena of the atmo- 

 sphere, which may be regarded as the fundamental basis of all meteorology; he 

 also ascended the Faulhorn, and there ascertained that mountains are possessed 

 of all the properties of forelands, and that consequently their resinous tension is 

 enormous. He explained the phenomenon of the coloring of mountains ; studied 

 the electrical phenomena of cascades ; caught a glimpse of the cause of the dif- 

 ferent colorings of clouds ; made, with M. Bravais and by request of M. Regnault, 

 experiments on tlie boiling point of water in reference to different heights ; and 

 finally returned to Paris laden with his numerous materials. Hardly arrived in 

 Paris, he gathered together, arranged, and made known all the facts he had 

 observed, and published his dissertation on the difierent kinds of fogs. 



In 1843 Peltier continued his labors, and prepared the memoirs with which 

 his scientific career terminated. 



November 2, 1844, he presented to the Brussels Academy of Science his great 

 work on the cause of barometrical variations, and his researches on cyano-polar- 

 imetry ; and this same year published in the Archives of EJcdrkity, at Geneva, 

 his memoir of electrical meteorology. He also made known to the Philomathio 

 Society his observations on the electricity of vapor arising from boilers at high 

 pressure ; pointed out the difierent causes of error which might deceive students 

 of meteorology, and added some points of detail to the general history of water- 

 spouts, on occasion of the Cette water-spout. 



Finally, in 1845, Peltier made knovv'nthe cause of the oscillations observed by 

 M. Liagre in spirit levels, and presented to the Brussels Academy of Science his 

 dissertation on the cause of electrical phenomena, which concluded his scientific 

 career, and which he unfortunately did not live to see in print. 



We have now terminated the principal discoveries made by Peltier in micro- 

 graphy, physics, and meteorology. All these works, all these researches were 

 effected at most in 20 years ; and, indeed, it can be said that his meteorological 

 labors only date from 1839. From having made so great a numl)er of discoveries 

 in so short a time, it is easy to understand in what a state of intellectual tension 

 Peltier must have passed his life. For several years previous to his death his 

 health had suft'ered much ; bat to all remonstrances of his friends and family he 

 replied: "I would rather die 10 years sooner and leave behind me discoveries 

 Avhich will recall my name." In the month of July, 1842, Peltier went to the 

 Faulhorn, there to make meteorological observations. The sudden change from 

 a t(!mperature of 30° above zero to one almost always below this point, mate- 

 rially affected his health, and, a short time after his return to Paris, resulted in a 

 spell of sickness. His disease was not in its first stages dangerous, being but a 

 slight intestinal affection, to cure which would have required at this time rest and 

 quiet for a few months. But with his character, with that incessant activity which 

 distinguished him, Peltier could not accept repose ; he could exclaim with Hoche: 

 ''Give me a remedy for fatigue, bat let it not be repose." Another canse there 

 was which added still to the excessive excitement of his brain : he had laid the 

 foundations of meteorology ; he had established the basis, and he now wished 

 to deduce its consequences and a[ ply them to the different phenomena of nature. 

 Kor was this all : it was long since he had had decided opinions on the nature of 

 electricity; but never having drawn them up into regular form, he was afraid 

 death miglit overtake him too soon for the work ; so that, redoulding his energy 

 and activity to accomplish his wish, his relapses became frequent, and his malady 



