450 Herschel's Catalogue of Nebulce. 



sometimes "be borne by the 6-foot. With the latter, he prefers 

 in these observations 1300, given by a lens of -g-inch 

 focus, to a lower magnifier. As to the fittest opportunity for 

 such researches he makes a singular remark, that in winter 

 the finest definition and blackest sky usually occur before 1 1 

 o'clock, after which time the sky becomes luminous, and the 

 fainter details of nebulae disappear : in spring and autumn the 

 change is neither so early nor so decided ; but the nights are 

 then shorter. Additional difficulty seems to be thus inter- 

 posed in the use of instruments of the highest light-grasping 

 quality ; nevertheless, the work which they alone can do is too 

 valuable to be relinquished so long as it is at all feasible. And 

 more, it seems, may still be within our reach. The best judge 

 that is, or ever has been, upon this subject, the noble fabricator 

 of the Parsonstown reflectors, expresses himself in this memoir 

 as of opinion that still larger instruments might be made, and 

 would be of service. After all that he has so munificently 

 done, more cannot be expected from him : whether any other 

 wealthy and spirited amateur will attempt a further advance 

 remains to be seen. In France, such endeavours receive 

 encouragement from public sources. At the first general 

 meeting of the recently-formed Paris Association for the 

 advancement of Astronomy and Meteorology, held June 3, 

 1864, when about 400 members were assembled at the 

 Observatoire Imperiale, it was decided that two discs of glass, 

 each 2 feet 5| inches (English measure) in diameter, should 

 be placed forthwith in an optician's hands, to be formed into 

 an object-glass, and a disc of 4 feet 14- inch, to be wrought 

 into a silvered speculum : the expense of one of these instru- 

 ments being defrayed by the Imperial government, and 15,000 

 francs granted towards the other, if met by a payment of 

 70,000 francs from the town to which it will be consigned. Our 

 own government at present takes a different view of these 

 matters* ; but it must be borne in mind that the number is far 

 greater in England than in France, of individuals whose 

 means would be largely available for the purposes of science ; 

 or, possibly (judging from the past), whose taste would direct 

 them into such a channel. Should these undertakings prove 

 successful, Cooke's 25-inch object-glass, now in progress, will 

 no longer be the largest in the world ; and though the Earl 

 of Posse's speculum will still be unrivalled in dimensions, the 

 greater reflective power of silver, and the superior transparency 



* The following anecdote of King George III., preserved by Lalandc, deserves 

 to be generally known. " Je fus U'moin du zele que le roi d'Anglcterre avait 

 pour l'astronomie ; il me dit que e'etait lui qui avait voulu que Ilerschel portat 

 son telescope jusqu'il 40 pieds ; et comme jc lui faisaia des remercimens pour les 

 astronoraes, il me lit cette reponse odifiante. 2fe vaut-il pas mieux employer son 

 argent (i eela qiCa foire liter des homines f" 



