PHILOSOPHICAL SOCIETY OF WASHINGTON. 213 



inclusive, tlio aurora was remarkably frequent and brilliant both 

 in Europe and in this country ; and that most of the auroras 

 described in the Annals for this time, particularly the brilliant 

 ones, were seen on the same evening in England and in the State 

 of New York." From which he argues that " these simultaneous 

 appearances of the meteor in Europe and America would there- 

 fore seem to warrant the conclusion that the aurora borealis can- 

 not be classed among the ordinary local meteorological phenomena, 

 but that it must be referred to some cause connected with the 

 general physical principles of the globe ; and that the more 

 energetic action of this cause (whatever it may be) affects simul- 

 taneously a greater portion of the northern hemisphere." * 



In attempting to classify and digest the meteorological data 

 within his reach, Henry became strongly impressed with the 

 necessity of much more extensive, continuous, and systematic 

 observations than any as yet undertaken : and he omitted no 

 opportunities of directing influence upon the minds of our 

 national legislators, to impress them with the great need — as 

 well as the practical policy of prosecuting the subject by govern- 

 mental resources. No one at that day seemed so fully awake 

 both to the importance and to the methods of prosecuting such 

 inquiry : and no one more effectually advanced both by direct 

 and by indirect exertions the wide-spread interest in this study, 

 than he. 



In 1839, while at Princeton, he induced the American Philo- 

 sophical Society officially to memorialize the National Govern- 

 ment to establish stations for magnetic and meteorological obser- 

 vations : a movement which was partly successful, though not to 

 the extent desired. On the subject of international systems of 

 observation and register, he justly remarks at a later date : " In 

 order that the science of meteorology may be founded on reliable 

 data, and attain that rank which its importance demands, it is 

 necessary that extended systems of co-operation should be estab- 

 lished. In regard to climate, no part of the world is isolated : 

 that of the smallest island in the Pacific, is governed by the 

 general currents of the air and the waters of the ocean. To fully 

 understand therefore the causes which influence the climate of 

 any one country, or any one place, it will be necessary to study 

 the conditions, as to heat, moisture, and the movements of the 

 air, of all others. It is evident also that as far as possible, one 

 method should be adopted, and that instruments affording the 

 same indications under the same conditions should be employed. 

 . . . A general plan of this kind, for observing the meteor- 

 ological and magnetical changes, more extensively than had ever 

 before been projected, was digested by the British Association 



* Sill. Am. Jour. Sci. April 1832, vol. xxii pp. 150-155. 

 VOL II. — 18 47 



