262 Proceedings of the British Association 



nebulae: but there are also some striking examples of dark holes in 

 bright matter, dark clefts in bright rays, and resolvability of apparently 

 nebulous matter into stars. 1 do not deny the importance of the last 

 observation ; but as it might be predicted beforehand that the increase 

 in the dimensions of telescopes would lead to more extensive resolution 

 of nebulse, I do not hold the inference to be by any means certain that 

 all nebulae are resolvable. Mr, Lassell exhibited at the last meeting of 

 the Association a plan for supporting his two-feet mirrors without flex- 

 ure. This plan, slightly modified, has been adopted in use: and I am 

 assured that the improvement in what before seemed almost perfect 

 definition is verj^ great. 



The removal of the vexatious fiscal interferences that have been con- 

 nected with the manufacture of glass, and the enterprise with which 

 Mr. Chance as manufacturer and Mr. Simms and Mr. Ross as opticians 

 have taken up the construction of large object-glasses, promise to lead 

 to the most gratifying results. Already Mr. Simms has partially tested 

 object-glasses of 13 inches aperture; and one of 16 inches is waiting 

 not for the flint but for the crown lens. Mr. Ross, it is understood, has 

 ground an object-glass of 2 feet aperture ; but it has not been tested. 

 The facility of procuring large object-glasses will undoubtedly lead to 

 the construction of graduated instruments on a larger scale than before ; 

 and it is in this view that I contemplate as a matter of no small impor- 

 tance, the erection (this year) of the large transit-circle at the Royal 

 Observatory at Greenwich, It is known to many members of the 

 Association that this instrument was constructed in this town, by Messrs. 

 Ransomes iSt May ; and for the admirable proportions of its various 

 parts, for the firmness of fitting of the few portions of which it is coai- 

 posed, and for the accuracy of the external forms of pivots, &c., it 

 may well be considered as one of the finest specimens of engineering 

 that has ever been produced. As an example of an excellent mechan- 

 ical structure carrying a large object-glass, I think it probable that this 

 Greenwich transit-circle may have a great influence on the construction 

 of future instruments. 



I had hoped to be able by this time to report to the Association 

 some account of the American method of recording transits, by a 

 puncture or dot produced by a galvanic agency whose circuit is closed 

 by a touch of the observer's finger, — and especially on its fitness for 

 the wants of a really active observatory : but the delays of construc- 

 tion have prevented me from doing so. Shortly before the last meeting 

 of the Association, the President for the time (Dr. Robinson) transmit- 

 ted to the government, on the part of the Association, a general request 

 that a large reflecting telescope might be sent to some of the British 

 possessions in the southern hemisphere, for the purpose of observing 

 the southern nebulae; and shortly after that meeting an answer was 

 received from the Lords of the Treasury, to the effect that their Lord- 

 ships entirely recognized the importance of the object, but that there 

 appeared to be practical difficulties in the immediate execution of the 

 design. I cannot doubt that when a more explicit plan has been formed, 

 another representation will be accompanied with the same success 

 which has attended every application made by the Association for aid 

 in a carefully arranged design. 



