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luj I L I B R A R Y . -pi 



WEEKLY EVENING MEETING,\^\ "^•^ /^ 



Friday, January 20, 1882. XT^'^ ^V^ 



George Busk, Esq. F.R.S. Treasurer and Vice-President, in tlieUEalr. 



William Huggins, Esq. D.C.L. LL.D. F.R.S. 



On Comets. 



In the olden time comets were looked upon as the portents of all 

 kinds of woe. In the words of Du Bartas, as rendered by Sylvester* : — 



" There with louo; bloudy haire, a Blazing Star 

 Threatens the World with Famin, Plague and War : 

 To Princes, death : to Kingdoms, many crosses; 

 To all Estates, ineuitable Losses : 



To Heard-men, Kot : to Plough-men, hap-lesse Seasons : 

 To Saylers, Storms : to Cities, ciuill Treasons." 



In the past year, including telescopic comets, no fewer than seven 

 of these blazing stars have threatened us, and certain contemporary 

 events might seem, indeed, to justify this view of their malign 

 influence. But though comets are no longer a terror to us, they are 

 still, in some respects, a great mystery. When we attempt to explain 

 the marvellous phenomeua they present, by the rigid ajjplication of 

 the laws of physics, we find ourselves confronted by prodigious diffi- 

 culties. We are almost led to think that in the heavens, at least, 

 there is more " than is dreamt of in our philosophy " — some profound 

 and still unknown mystery of nature. Not to mention the many 

 absurd theories which are heard on all sides when a great comet 

 appears, on no phenomenon of nature have we so many guesses at 

 truth by the masters of science on different and even ojiposing prin- 

 ciples of explanation. At the present moment there is no consensus 

 of opinion as to the nature of comets. 



But within the last few years, from two oj)posite directions — 

 from the use of the spectroscope and from mathematical investigation 

 applied to the periodical displays of shooting stars — much knowledge 

 has been gained of their nature, though there are still many points 

 on which we can only speculate. 



It is my pur^Dose this cveniug to give chief prominence to the new 

 knowledge which these two methods of research have placed within 

 our reach, and to distinguish as clearly as may be possible between 

 what we know about comets and wOiat is not more than speculation. 



To carry out this purpose we must first study carefully the phe- 



* Du Bartas, translated by J. Sylvester, fol. 1621, p. 33. 

 Vol. X. (No. 75.) 



