SKETCH OF DENIS ON OLMSTED. 407 



liglit to substantially the same origin. These views, however, as 

 Prof. Silliman observes, were mostly thrown out only as con- 

 jectures, and not as formal theories to be held and defended. 



Previous to this. Prof. Olmsted had interested himself in 

 meteorological studies. In 1830 he published in the American 

 Journal of Science a new theory of hailstones, in which he as- 

 cribed the origin of those formations to the sudden mingling of 

 large bodies of hot and humid air with air extremely cold, by 

 which the vapor of the former would be rapidly condensed and 

 congealed into hail. These effects, he assumed, would be pro- 

 duced whenever, by means of opposing winds, whirlwinds, or 

 other atmospheric disturbances, hot air should be brought above 

 the line of congelation or cold air brought below it. 



He agreed with Redfield in supposing that ocean gales are 

 progressive whirlwinds ; and he believed that he had established 

 their laws or modes of action on an impregnable basis. This 

 view of storms as progressive whirlwinds still holds good as a 

 generalization ; but his further ascription of the ultimate causes 

 of atmospheric disturbances to the diurnal and orbital motions 

 of the earth has not found an accepted place in science. Prof. 

 Olmsted had a close friendship and a warm sympathy with Mr. 

 Redfield, with whose views respecting the rotatory motions of 

 storms he agreed ; and he read an affectionate memorial of him 

 before the American Association, at Montreal, in 1857. 



Prof. Olmsted and Prof. Loomis, who was then a tutor in the 

 college, were the first persons of all observers to find Halley's 

 comet on its return in 1835. One of the results of this observa- 

 tion was the awakening of an interest in procuring larger and 

 improved telescopes. It did not bring immediate fruit, it is true. 

 The project already conceived for the establishment of a perma- 

 nent observatory at Cambridge, to which it gave a new impulse, 

 was not yet to be made real. There were other circumstances, 

 however, than want of interest in astronomy that kej^t such lib- 

 eral schemes from being carried out the country and the uni- 

 versities had not grown up to them, and the needed abundance 

 of money had not yet come but this was one of the incidents 

 that kept the movement vital and sped it on. Prof. Olmsted also 

 conceived a plan for the establishment of an observatory at Yale 

 College, which should have two departments : one to aid in the 

 instruction of students and the other for the use of scientific ob- 

 servers; but the time had not yet come for this. As another 

 incident of his astronomical work. President Woolsey relates 

 that " for a number of years, until his health forbade it and his 

 eyesight began to fail, he was accustomed to gather his class 

 around him on a bright autumn evening and introduce them to 

 the heavenly bodies. In this way he endeavored to train up a 



