150 Transact ions, — Miscellaneous. 



Art. XV. — On the Zodiacal Light, as seen in Southern Latitudes. 



By Henry Skey. 



[Read before the Olago Institute, 14th September, 1874.] 



Not only lias the science of astronomy received a most remarkable impetus 

 by the use of the spectroscope, but that of meteorology has been extended 

 likewise, so that from treating only of mundane or terrestrial results — as the 

 weather — it now claims within its domain the magnificent phenomena of solar 

 atmospheric action, the physical formation of stars, comets, and meteors, and 

 even to the bounds of the known universe it ascertains without a doubt the 

 gaseous constitution of some of those distant nebulse and the remarkable 

 changes which they undergo. 



Intimately connected with these subjects may be considered the invest i- 

 gations on the nature of the zodiacal light. In a previous paper* on this 

 subject a theory w r as advanced in which the elongation of the medium of this 

 remarkable illumination was attributed to the action of an interstellar and 

 resisting medium upon the heat-repelled constituents of the solar atmos- 

 phere, thus causing a portion thereof to drift in rear of the sun's proper 

 motion, whereby it would cease to retain the diurnal rotation and tend towards 

 an orbital motion ; and the times of visibility of this light in the northern 

 hemisphere, as given by Herschel, were adduced as leading to the conclusion 

 that in the month of November the earth must pass near if not actually 

 through it annually, the November meteors being instanced as the result of 

 the collision. A diagram was also givent explaining its appearance as seen 

 from the northern hemisphere. 



In November, 1872, Mr. Webb gave an interesting account of the most 

 recent observations on this light,J stating that it was visible in some parts of 

 the earth nearly all the year round. The accounts therein given do not, 

 however, furnish us with the amount of elongation, nor mention whether that 

 elongation is constant, nor yet inform us whether it is visible in the mornings 

 and evenings of the same day, and the time of year that it is invisible ; and 

 as these data are necessary in order to ascertain the true shape of the zodiacal 

 envelope I therefore commenced tabulating what could be observed on these 

 points in our southern latitude from 1872, the results of which are 

 appended : 



1872, July 2nd — An illumination along the ecliptic was observed in the 

 western part of the sky at 7.30 p.m. It was nearly as bright as all but the 

 brightest portion of the Milky Way, which was also very brilliantly shining. 

 The air was very transparent and the hygrometer showed saturation. The 



* Trans. N.Z. Inst, Vol. V., App. p. xliii. + Vol V., pi. XIV. £ Vol. V., 



App. p. xlvn. 



