Proceedings of the British Association. 123 



proper that there should be a yielding where necessary, or contact 

 would not be preserved. Both conditions can be satisfied by forming 

 the surface of two layers of resinous matter of different degrees of 

 hardness ; the first may be of common pitch, adjusted to the proper 

 consistence by the addition of spirits of turpentine, or rosin ; and the 

 other I prefer making of rosin, spirits of turpentine, and wheat flour, 

 as hard as possible, consistent with its holding the polishing powder. 

 The thickness of each layer need not be more than one-fortieth of an 

 inch, provided no portion of continuous surface exceeds half an inch 

 in diameter, the hard resinous compound, after it has been thoroughly 

 fused, can be reduced to powder, and thus easily applied to the 

 polisher, and incorporated with the subjacent layer, by instantaneous 

 exposure to flame. A speculum of three feet diameter thus polished, 

 has resolved several of the nebula?, and in a considerable proportion 

 of the others has shown new stars, or some other new feature." 



In conclusion, Lord Rosse exhibited drawings of the nebulae, as 

 figured by Herschel, and also as they appeared in the telescope con- 

 structed by his Lordship. 



Fig. 88, of Herschel, or 2 Mesier, and 21h.25m. g— 1° 34' south 

 many of the stars into which it is reduced by his telescope, are as 

 large as those of the first magnitude to the naked eye. 



Fig. 81, Herschel, the bright nebula near £ Tauri, figured by 

 Herschel as perfectly elliptic and resolvable, but no stars seen, is seen 

 in the telescope, with three -feet aperture, as a rather oval cluster of 

 stars, with projecting filaments of stars, some of these filaments 

 extending considerably, so as to give something of the idea of a 

 scorpion. 



Fig. 29, of Herschel. The ring nebula of Lyra, shows in the three - 

 feet telescope, seven stars, one triple. It is an annular cluster, with 

 fringes, and the nebulous-looking centre in patches. 



Fig. 45, of Herschel, a planetary nebula, is also seen as anannular 

 cluster. 



Fig. 26, of Herschel, the " Dumbell Nebula," is seen as an irregu- 

 lar cluster, or rather two in juxta-position, and nothing of the exact 

 elliptic termination of Herschel's figure. 



Dr. Robinson and the Marquis of Northampton briefly addressed 

 the section. 





