ASTRONOMICAL PHENOMENA AND PROGRESS. 



Signal Service, an expedition for observation 

 was sent to Mount Whitney, in the Sierra Ne- 

 vadas of Southern California. In "Nature " for 

 August 3, 1882, Professor Langley, after giving 

 an interesting account of the journey from 

 Pittsburg to Lone Pine at the foot of the Si- 

 erras, and of the laborious ascent of Mount 

 Whitney, makes a preliminary report of the 

 results derived from simultaneous observations 

 at points differing more than two miles in alti- 

 tude. He says : 



It appears probable that the true solar constant is 

 one halt greater than that determined by Pouillet and 

 by Herschel near the sea-level, and even greater than 

 the recent values assigned by M. Violle. The true 

 value, it is believed, will be shown by the data when 

 published to be larger than those hitherto accepted. 



Of more general interest, perhaps, is the conclusion 

 as to the limit of that cold which increases under 

 full sunshine as we ascend above our atmosphere. 

 "What," it may be asked, "would the temperature of 

 the soil be on a mountain-top rising wholly above the 

 air, or what the temperature of the sunward hemi- 

 sphere of the earth, if the present absorbing atmos- 

 phere were wholly withdrawn?" The personal ex- 

 periences already alluded to may prepare the general 

 reader for the paradoxical result that, if this atmos- 

 phere were withdrawn, the temperature would greatly 

 fall, though under a materially greater radiant heat. 



The student of the subject is aware that this con- 

 clusion follows from the fact that the loss by radiation 

 into space as the atmosphere is withdrawn is much 

 more rapid than the gain by direct solar heat, but 

 even he may not perhaps be prepared for the extent 

 of the fall. 



The original observations, which will be given at 

 length, lead, in the writer's opinion, to the conclusion 

 that in the absence of an atmosphere the earth's tem- 

 perature of insolation would at ary rate fall below 

 -50 Fahr., bv which it is meant that (for instance) 

 mercury would remain a solid under the vertical rays 

 of a tropical sun were radiation into space wholly un- 

 checked, or even if, the atmosphere existing, it let ra- 

 diations of all wave-lengths pass out as easily as they 

 come in. Kemembering, then, that it is not merely 

 by the absorption of our air, but by the selective 

 quality of this absorption, that the actual surface tem- 

 perature of our planet is maintained, we see that, with- 

 out this comparatively little-known function, it ap- 

 pears doubtful whether, even though the air support- 

 ed respiration and combustion as now, life could be 

 maintained upon this planet. 



These conclusions do not, in the writer's opinion, 

 depend upon the Mount Whitney observations alone, 

 but exist implicitly in the results of previous observ- 

 ers, who have, however, not apparently drawn them, 

 with the exception, perhaps, of Mr. Ericsson, who has 

 observed that the surface of the airless moon must re- 

 main cold even in sunshine. 



We see, if these results be true, that the tempera- 

 ture of a planet may, and not improbably does, de- 

 pend far less upon its neighborhood to, or remoteness 

 from, the sun, than upon the constitution of its gas- 

 eous envelope, and indeed it is hardly too much to 

 say that we might approximately indicate already the 

 constitution of an atmosphere which would make 

 Mercury a colder planet than the earth, or Neptune 

 as warm and habitable a one. 



It must at the same time be admitted that our in- 

 formation as to the special constituents of our own air, 

 which are chiefly here concerned, is still imperfect 

 though the observations made at Mount Whitney upon 

 the selective action of that undoubtedly prominent 

 agent, water-vapor, will, it is hoped, add somewhat 

 to our knowledge. 



In the same connection it may be added that the 



T-iter's investigations have led him to the conclusion 

 that the temperature of space, so called, must at any 



rate be lower than that assigned by Pouillet (if we ac- 

 cept the received values for that of the absolute zero), 

 and in this case the temperature of the earth's surface, 

 in the absence of the quality of selective absorption in 

 our air, will be yet lower than that here given. 



AURORAS. Auroral displays in 1882 were 

 more brilliant as well as more numerous than 

 had been observed for several years. Some of 

 the brightest occurred at the following dates : 



April 16th-17th. A magnificent aurora was 

 seen throughout the United States, whenever 

 the sky was clear, from nine o'clock on the even- 

 of the 16th till daylight on the morning of the 

 17th. The varying aspects of the phenomenon 

 are described in the " August Observatory " by 

 Professor Larkin, of New Windsor, 111., who 

 watched it from its first appearance till after 

 four o'clock the next morning : 



From midnight to 1 A. M., April 17th, the phenome- 

 non was at its height, the whole northern heavens 

 from the horizon to the equator being striped and 

 banded with varying streams flashing incessantly. A 

 wave of light would appear in the northern horizon, 

 and instantly rush to the zenith, producing curvature 

 in the straight columns, which at once resumed their 

 original position when the wave passed, only to be 

 wrought again in a few seconds. 



The whole northern hemisphere quaked with the 

 rapidity of lightning without cessation during the 

 hour following midnight, each upheaval impelling 

 light-emitting matter to the zenith, where it was no 

 longer agitated, but floated slowly south. Much of 

 this actually descended as far as Scorpio 30 south dec- 

 linationj so that nearly the entire celestial vault was 

 filled with the coruscations. This unparalleled dis- 

 play of auroral activity was still in motion at 4 h - 30 

 A. M., when the solar rays obscured the scene. The 

 sun-spot turbulence, the aurora, and a magnetic storm, 

 occurring all at one time, seem to indicate a bond of 

 union between solar and terrestrial energy, the secret 

 of which yet eludes research. The perpetual flashing 

 of the heavens was the most marked feature of the au- 

 rora, giving rise to a scene of appalling grandeur and 

 sublimity. 



April 17th, 6 h ' 35 m- P.M. A brilliant aurora 

 australis was seen in New Zealand. It is re- 

 markable that this was almost, if not quite, 

 contemporaneous with the aurora borealis 

 above described. 



May 14th, ll h - 15 m - p. M. This display was seen 

 in England. A very bright streamer shot up 

 from the horizon beneath Cassiopeia, covering 

 without hiding that constellation. Numerous 

 white, flickering streamers extended rapidly to- 

 ward the northwest, overspreading the north- 

 ern hemisphere from Cassiopeia to Gemini. 



May 18th, from 12 to 1 o'clock, A. M. A 

 bright aurora was seen in Scotland. 



On August 4th, from 10 h - 30 m - to 1 l h> p. M. A 

 fine aurora was seen in Scotland. 



October 2d. A very bright aurora was seen 

 in England on the evening of October 2d. 

 Shortly before seven o'clock a bright arch ex- 

 tended along the northern horizon to a height 

 of 20. From this arch " remarkable outbursts 

 of streamers" shot up at intervals toward the 

 zenith, the most active movements correspond- 

 ing closely in point of time with the violent 

 magnetic disturbances of the same evening. 



November 13th. A grand auroral display 

 was witnessed in New York and other North- 



