44 ASTRONOMICAL PHENOMENA. 



AURORA BOREALIS. 



tived by the spectroscope, for no two spectra can be 

 more essentially different than those of the aurora 

 and the zodiacal light. They are as different from 

 one another as night from day. 



The results of observations of the zodiacal 

 light, at Rio Janeiro and various places upon 

 the high plateau in the interior of Brazil, are 

 given, in a note to the Comptes Rendus, by Mr. 

 E. Liais. He finds that the light is visible as 

 far as the anti-solar point of the heavens. Po- 

 lariscopic observations have not enabled him 

 to discover any trace of polarization. He has 

 also, at various times within the last four years, 

 studied the light, by the aid of the spectro- 

 scope, and has found that it gives a spectrum 

 apparently continuous, though perhaps con- 

 taining dark lines. 



These results would indicate that the light 

 is derived from the sun by reflection ; and the 

 absence of polarization, if certainly made out, 

 shows that the matter reflecting the solar rays 

 is not gaseous, but made up of solid corpuscles 

 not endowed with the properties of specular 

 reflection, but scattering the light irregularly. 

 With regard to the connection between the 

 base of the zodiacal light and the corona, he 

 remarks that, although the light in the latter 

 is polarized, while that of the former is not so, 

 a fact indicating that the latter is gaseous, and 

 the former composed of solid particles, the 

 corona may possibly be the base of the zodi- 

 acal light, its gaseous condition being a result 

 of its proximity to the sun, in consequence of 

 which the solid particles are volatilized by the 

 intense heat. 



Luminous Matter in the Atmosphere. In 

 observations of the sun during eclipses, and 

 also in ordinary daylight, luminous particles 

 in large numbers are often seen, and their 

 appearance has given rise to many conjec- 

 tures. Mr. Henry Waldner has paid much 

 attention to the subject, and writes in ex- 

 planation to Nature. His first acquaintance 

 with these particles was made in directing 

 his telescope to the sun, to observe spots, 

 when, just as he was about getting the disk in 

 field, he perceived a mass of luminous little 

 bodies, apparently coming from the sun, and 

 passing with great velocity toward the east. 

 They emitted a white and sparkling light, and 

 were as numerous as stars, and moved rapidly. 

 On subsequent observation of this same phe- 

 nomenon, he became satisfied that they were 

 ice-crystals or flakes of snow floating at a dis- 

 tance from the earth's surface of about 4,000 

 metres down to 200 metres, and having an 

 average diameter of 32 millimetres, and a ve- 

 locity of two metres a second. They were 

 seen most abundantly from April 20th to May 

 15th, and then again in August and Septem- 

 ber. Upon these facts the author thus specu- 

 lates : 



Here it may be recollected that already, in the 

 seventeenth century, Mariotte,the renowned discov- 

 erer of the law of gas-expansion, pointed out that 

 parhelions and mock moons are caused by ice-crys- 

 tals floating in the sky ; and, indeed, if we consider 



the above results, we are forced to believe him. 

 Firstly, we learned that these bodies belong to the 

 atmosphere ; we also found them in its lower strata. 

 Their average size of 32 millimetres^ their flake-like 

 shape, their incalculable number, will also strongly 

 convince us. But, while the minimum during the 

 winter months might seem rather unaccountable, the 

 chief maximum occurring in April and May, it may 

 be remarked that from September to March the sun, 

 although in the meridian, does not light up so 

 strongly the rather misty sky, and that many days 

 the sun will not appear at all. Now, referring to the 

 chief maximum, from about April 20th to May 15th, 

 is it not astonishing that it occurs on the very same 

 days which, especially those of May, were at all 

 times well known from their low temperature, and 

 called, in Germany, " the Latins " (Pancratius, May 

 12th, Servatius, May 13th, etc.), and were much 

 feared by gardeners ? But, are the enormous masses 

 of ice-crystals, found in the atmosphere during these 

 days, the origin of its low temperature ? or, does the 

 latter favor the formation of snow-masses ? I only 

 mention the fact that, for instance, heat is absorbed 

 when snow is melting, and would be happy to direct 

 the attention of meteorologists, in any country, to 

 this phenomenon, inviting contributions of facts and 

 correspondence. Finally ^ the velocity of the bodies 

 being the same as that of the clouds, their reflected 

 magnificent white light, the irregular courses in the 

 higher regions, where strong winds are generally 

 blowing, their irregular or even falling movement, 

 and small density, m the lower ones, and their very 

 remarkable conformity of direction with simultane- 

 ously-passing clouds/will give much support to my 

 explanation. 



AURORA BOREALIS. An auroral display 

 of remarkable brilliancy, visible throughout 

 Europe, the British American possessions, and 

 the Northern part of the United States, 

 occurred on the night of February 4th. It 

 lasted about four hours, and exhibited all 

 the beautiful shifting forms and colors known 

 to such phenomena. Fortunately, it was ob- 

 served with great care by numerous competent 

 persons, and we have, in the English scientific 

 journals, a complete record of its varying ap- 

 pearances, and the concurrent indications. The 

 telegraphing business in England was greatly 

 deranged. Strong deflections, from earth-cur- 

 rents, were noticed on all circuits except the 

 local ones. The duration of the currents changed 

 from north to south at intervals of a few min- 

 utes, and varied in strength from 1 to 68, the 

 strength of the current being proportionate to 

 the length of the wire. Lines running south- 

 west and west appeared to be most affected. 

 The French Atlantic cable felt the disturbing 

 electric influence ; the strength of the current 

 at one time being equal to 90 Daniell cells. 

 The wires in France were much affected, and 

 the American telegraph-lines were disturbed 

 in the East, West, and North, where the aurora 

 was most distinctly seen, but not in the south. 

 The magnetic storm accompanying this great 

 aurora commenced in England about 2 p. M., 

 and was at its height from 4 to 9, although 

 the magnets were not steady again until after 

 sunrise the next morning. The usual yellow- 

 ish-green auroral line was distinct everywhere, 

 and could be seen even when the spectroscope 

 was directed to dense masses of cloud ; and 

 could be made out in the reflection of the light 



