Proceedings of the British Association, 1 1 7 



this differential motion takes place in the direction in which the 

 veined structure exists, and that it is impossible not to consider the 

 one phenomenon as dependent on the other. 



The discussion on this paper occupied two hours, and till the meet- 

 ing closed, when it was arranged that it should be resumed on 

 Saturday, at the sitting of the section, when the subject again 

 occupied the attention of the section for upwards of three hours. 



In consequence of the more than usual interest which attached to 

 the proceedings of this section on Monday, when the Earl of Rosse 

 described the construction of his gigantic reflecting telescope, we 

 shall so far deviate from our custom, of reporting the proceedings 

 according to the order of their occurrence, as to give this paper 

 at once. 



Long before the hour of meeting, the room was crowded to suffoca- 

 tion, and many ladies, and even gentlemen, could not gain admit- 

 tance. The address was illustrated by a model, with its supporting 

 piers and galleries complete, and by a working model of the grinding 

 and polishing machine. 



The Earl of Rosse commenced by stating, that the Council hav- 

 ing intimated their opinion that some account of the experiments in 

 which he had been engaged on the reflecting telescope would not be 

 altogether devoid of interest, he would endeavour to describe, as briefly 

 as possible, the manner in which he had attempted to accomplish the 

 object in view, and the principal results obtained. When, about the 

 year 1826, he first turned his attention to this subject, he considered 

 that the knowledge of our own system might be almost consider- 

 ed complete. There were, no doubt, some portions of it, as the 

 motions and distances of the satellites of Uranus, the masses of some 

 of the planets, the rings of Saturn, and some others, which yet 

 required elucidation, and would doubtless amply reward industrious 

 research ; but on the whole, he conceived that our ordinary instru- 

 ments, aided by the nice contrivances for accurate measurement 

 which the perfection of modern art had introduced, were amply 

 competent to aid in this branch of research the many men of genius 

 who were engaged in it. But a new and a most interesting field had 

 been opened to the view, and partially explored, by the indefatigable 



