CERTAIN HARMONIES OF THE SOLAR SYSTEM. 65 



An example of our Case ^d. " The clearest defined portion" was nearly oppo- 

 site to the moon, then 3| days past the full, and Ij day beyond the apogee. 



" March 7. With regard to the earliest visibility of the light, it was not notice- 

 able till 15m. after stars of the brightness of y Arietis had shone out, and not 

 quite so soon as the Milky Way at equal altitudes. Its whiteness more dusky 

 than the latter. At an altitude of about 20°, jy and a Piscmm (the latter just 

 within the boundary) were somewhat dimmed by its intensity." 



This is followed by another JSote on tlie Zodiacal Light, by E. B. Knobel, Esq., 

 who writes from Stapenliill Burton on Trent, and says: "I would beg to direct at- 

 tention to the unusual brilliancy of the Zodiacal Light this winter. . . ." On two 

 clear evenings in the first week in January, on January 17, at 6.45 P. M., and, lastly, 

 on Feb. 8, at 7 P.M., it appeared as an elongated luminous cone, the apex of which, 

 on January 17, extended nearly to the star y Arietis, and on Feb. 8, the apex just 

 enclosed vj Piscmm. 



" It appeared nearly as bright as the Milky Way, and sufficiently bright to attract 

 the attention of a casual observer. 



"I should mention that my situation is quite away from the town, and sufficiently 

 high to be above the mists of the valley." 



The observation of Jan. 17 aff'ords another good example of our Case \st ; the 

 date being a little more than | a day before Neio Moon, and about 3 days before 

 the moon arrived at the Perigee. 



The observation of Feb. 8 confirms that of Rev. Samuel J. Johnson of the same 

 date, previously quoted. 



These observations are, moreover, all confirmatory of those made about the same 

 time, as well as at other dates, at the College of New Jersey, by the author of this 

 paper; and which, indeed, furnished the data for the distinction of the various 



[A very little observation will suffice to make it very evident, that under circum- 

 stances in other respects entirely similar, the fact of the atmosphere being dry will 

 notably afi^ect the apparent extent as well as brightness of the Zodiacal Light; 

 in accordance with the special, and even uniform, experience of Col. Forshey, 

 already referred to in (72) and Note.'] 



(92) Chaplain -Jones also speaks of pulsations in the Zodiacal Light ; as having 

 been observed by himself and others. His synopsis of these observations at p. 

 XIII of his Introduction is : " Some time early in 1854 I saw in a newspaper a 

 brief notice of the pulsations of the Zodiacal Light seen at Ivew Observatory ; but 

 as the newspaper did not state where they were observed, or the authority, and as 

 I had now been observing for a year without having noticed anything of the kind, 

 I set it down as an ocular deception, and the thing passed entirely from my mind. 

 But in March of this year (see No. Ill), I was surprised, one evening, at seeing 

 the Zodiacal Light fade sensibly away, dimmed to almost nothing, and then gradu- 

 ally brighten again. This was repeated several times ; but the effect, after all, 

 was to leave me only in amazement and doubt ; subsequent nights, however, gave 

 abundant exhibitions of this kind, of which, with the times and changes, I have 



9 January, 1875. 



