Oct. 1 8, 1888] 



NATURE 



595 



of the apparent apex of the zodiacal light from the sun. 

 It will be seen that each sun-spot minimum corresponds 

 with a maximum of the zodiacal light, and each sun-spot 

 maximum with a minimum of the zodiacal light. The 

 minimum in 1870 must be considered as masked by the 

 forces tending to produce the enormous maximum of 

 1876. It will be noticed, too, that when the sun-spot 

 phenomena are more extensive, as in 1850 and 1870, the 

 following zodiacal light phenomena are also more exten- 

 sive ; where the sun-spot phenomena are less, as in i860, 

 the following zodiacal light phenomena are less extensive ; 

 and per contra, when the zodiacal light phenomena are 

 extensive, as in 1880, the sun-spot phenomena are less 

 extensive. As far as this series goes, the correlation 

 seems to be complete. 



We may gain some insight into the relation by tabu- 



lating the various spectroscopic observations in their 

 order in the sun-spot cycle. Thus we have Lias, for four 

 years during the rise in the sun-spot period, observing 

 only a faint continuous spectrum ; Respighi and Lockyer, 

 just after sun-spot maximum, one bright line ; Vogel, the 

 same ; Smyth, Seech i, Pringle, about the same date, no 

 spectrum, or only a continuous spectrum ; Tacchini, pos- 

 sibly a bright line ; Wright, three years after maximum, 

 generally only a continuous spectrum, — three times a 

 bright line ; Burton, fourth year after sun-spot maximum, 

 continuous spectrum ; generally a bright line ; Arcimis, 

 five years after sun-spot maximum, continuous spectrum 

 and two bright lines' (1480 K and 2270 K). It would 

 seem, therefore, that the zodiacal light is more gaseous at 

 sun-spot minimum, and only slightly, if at all gaseous, at 

 and near sun-spot maximum. 



W w ~ ■ /: 



a , 1 



^ „" / l 



a 90 - ; I 



** - I \ 



I \ 



? 80 — / \ 



\ - , 

 2* 70 — 



; V 



/ \ 



/ \ 



/ \ 



I \ 



1 \j 



1 \ \ 



\ 1 



\ 1 



>l 1 1 1 I8l50i 1 1 iV8l55i/ l 1 1 I8l60i 1 1 



\ / 



\ / 



\ / 



\ I 



>, ii 1 1 I8l70i 1 1 1 I8l75l 



1 18801 1 1 1 



Comparison of zodiacal light elongations with Wolfs relative sun-spot numbers. 



The same story is told by the disturbances suffered by 

 Encke's comet. 1 



We would consider, therefore, the zodiacal light a 

 locus of condensation. 



One may notice, too, that the light appears, in common 

 with the frequency of aurone and the diurnal range of the 

 declination-needle, to be affected by a disturbance of 

 longer period. But for the present we must restrain our- 

 selves from the connections with terrestrial and cosmical 

 physics with which the matter teems, and ask— what is 

 the principal object of this communication — that those 

 wh:> ire not observing will observe, and that those who 

 have, or know of the places of concealment of, any 

 observations, will kindly call them to our attention. 



Baltimore, Md. O. T. Sherman. 



1 Goiihi's Astronomical Journal. 



CHEMISTRY AT THE BRITISH 

 ASSOCIA HON. 



IT was hardly to be expected that the proceedings of 

 the Chemical Section of the British Association would 

 be as remarkable at Bath as at Manchester. Nevertheless, 

 at Bath some interesting discussions took place, and some 

 valuable papers were read. 



The President's Address was listened to with great 

 interest, and formed a fitting introduction to the dis- 

 cussion, which afterwards took place, on the teaching of 

 chemistry. 



In the "Report of the Committee on the Action of 

 Light on the Hydracids, in Presence of Oxygen," read by 

 Dr. Richardson, some experiments were described, in 

 continuation of those read before the Association last 



