APPENDIX. V 



phenomena supposable in the case of transmission. The illumi- 

 nation will therefore be the most intense in the general direction 

 of the transmitted beams ; i. e., in this case, in the plane of the 

 ecliptic, or else parallel to that plane ; the appearance being 

 closely analogous to that which we see in the atmosphere, when 

 the sun illuminates the partially transpareat vapors through the 

 I'ifts in the clouds, and thus produces the appearance familiarly 

 described as "the sun's drawing water." 



The light being transmitted, other phenomena would also be 

 in place, among which are absorption — possibly interference, and 

 also fluorescence; new waves of light being originated in this case, 

 as well as, perhaps, in that of the comets, the spectrum-analysis of 

 whose light seems to show, among other phenomena, characteris- 

 tics of self-luminous material. 



To this it may now be added that the nebulous ring of chap- 

 lain Jones may well be regarded as having not indeed the lentic- 

 ular form attributed by older hypotheses, and which he does not 

 claim, nor a ring like that of Saturn, nor yet a ring of greater 

 thickness, though partially luminous indeed in appearance, as 

 Mr. Jones would have it, hat what may rather be termed a girdle, 

 of no great thickness it may be, but yet of very considerable 

 width; such as will provide for the breadth of the zodiacal light, 

 and the e.xtended elliptical spot opposite to the sun, which con- 

 stitutes " gegenschein," and which latter would seem to be almost 

 wholly due to reflection. Such a girdle, moreover, could not 

 always — perhaps hardly ever — have all its breadth enveloped in 

 the earth's shadow. There may also be some reason to suppose 

 that the curvature of the girdle, on one side at least, is such as 

 would be due to a portion of a spheroidal shell such as has here- 

 tofore been described in connection with other things connected 

 with the exposition of certain harmonies of the Solar System. 



But the question at once becomes a pertinent one. How can 

 such a girdle escape destruction by the continued perturbation 

 of the moon, acting in close proximity? The answer to this 

 question may be found, if the girdle be so situated that its time 

 of revolution around the earth shall be equal to the periodic 

 time of the moon. 



What is requisite for the fulfilment of that condition will first 

 be considered, and then the phenomena that seem to be accordant 

 with its actual fulfilment. 



The middle line of the girdle will form an oval, or rather con- 

 sist of two half ovals somewhat difi'erent in curvature. The half 

 oval nearest the moon may pass between the moon and the earth, 

 as in Fig. 1, or else outside of the moon, as in Fig. 2 ; in both 



sun's eqnator — in some sucli way as light, is caused to appear in radial 

 lines through and heyond the li^-ads of coniets, our power of theorizing 

 from such conclusions as have been dealt with in this paper, would be 

 limited." 



(23) 



