TO KNOW THE STARRY HEAVENS 



307 



rived particles. If this is the true ex- 

 planation of the Counter-Glow its dis- 

 tance from the earth must be 930,000 

 miles — four times the distance of the 

 moon. 



Fig. 3 — The planet Saturn. The small black circle 

 shows the earth drawn lo the same scale. 



Another, wholly different, theory 

 supposes that these particles directly 

 opposite the sun are molecules of the 

 lighter gases of the earth's upper at- 

 mosphere which are continually driven 

 away by the sun's action. If this is the 

 true explanation, the earth as it passes 

 about its orbit is, like many of the com- 

 ets, ever accompanied by a great but 

 very tenuous "Tail," which stretches 

 out into space in a direction exactly op- 

 posite to that of the sun. 



Amateur Observations. 



The Zodiacal Light and the Counter- 

 Glow are two excellent examples of ce- 

 lestial objects which seem especially 

 designed for the observation of amateur 

 astronomers. In this work even the 

 largest telescope is not of the slightest 

 use, and though the latter object has 

 been photographed, yet for their con- 

 tinual observation reliance must be 

 placed wholly upon naked eye work. 

 One observer has recently completed a 

 long series of zodiacal light observa- 

 tions, having special reference to it'^ 

 brightness, which latter is determined 

 by comparing it with selected regions 

 of the Milky Way. These observations 

 may in the future throw much light on 

 its irregular fluctuations in brightness, 

 which phenomena are as yet unexplain- 

 ed. 



Again, it is of much importance to de- 

 termine whether its axis lies exactlv 

 along the ecliptic, for one theory of its 

 origin supposes that its particles are 



expelled from the poles of the sun's 

 e(|uator. If this theory is correct, the 

 axis must be inclined to the line of the 

 ecliptic no less than seven degrees, for 

 this is the amount of the inclination 

 of the sun's equator. It has not yet 

 been determined from observation 

 whether this is the case. 



Like a Rainbow in the Frosty Air. 



BY H. A. BADGER, D.D.S., TICONDEROGA, 

 NEW YORK. 



As I sat at my breakfast table this 

 morning. Old Sol was just showing his 

 face over that historical Mount Defiance. 

 There was a a good bit of frost in the air, 

 and as the sun ishown on it an almost per- 

 fect spectrum was formed. I say almost 

 perfect for the blue and violet were 

 missing. This remained for almost 

 half an hour when the fall of frozen 

 particles of moisture ceased. My first 

 thought was to write you of it. ]\Iy 

 mother said that she has never heard 

 of nor seen anything of the sort before. 



[The presence of ice crystals in the 

 air frequently gives rise to beautifully 

 colored figures in the vicinity of the 

 sun and of the moon, — haloes, so-called 

 "Parhelic Circles," mock suns, and coro- 

 nae, — and sometimes to a combination 

 of several of these, making a striking 

 sky figure. Many will remember the 

 striking solar corona of about a year 

 ago, and on the evening of the last 

 eclipse of the moon, (January 8), there 

 was a fine lunar halo visible from east- 

 ern Pennsylvania. (A very satisfac- 

 tory account of these various appear- 

 ances may be found in Loomis' Meteoro- 

 logv. Pages 214 to 225.) 



Your correspondent does not state 

 the position of the colored appearance 

 with reference to the sun, but it may 

 perhaps be assumed that it appeared 

 between him and the rising sun, and 

 that it had the form of an arc of which 

 the sun was the center. If this is the 

 case it was the regular Primary Halo ; 

 if there were two principal regions 

 above the sun, these were probably 

 parts of the so-called "Contact Arches." 

 A small sketch of any unusual appear- 

 ance like this, will almost always en- 

 able its exact nature and explanation 

 to be told.— E. D.] 



