124 



tioned in Dr. Robinson's former communication, were exa- 

 mined. Of these, Nos. 505, 540, 668, and 988 of Herschel's 

 catalogue are mere globular clusters : 65 and 66 Messier are 

 of the other class, which he considers to be central clusters, 

 surrounded by discs of smaller stars seen obliquely. The first, 

 however, is less elliptic than in Herschel's fig. 53. 1 Messier 

 was examined, but little addition can be made to Lord Rosse's 

 description of its appearance in the three feet,* except that 

 the " nebulosity" is all resolved, and " the resolvable fila- 

 ments" consist of pretty large stars. There is, however, in the 

 body of the cluster one so much larger than the rest, that it 

 can hardly belong to their system. 



The great nebula of Orion was completely resolved in 

 those places which presented the mottled appearance, even in 

 indifferent nights, and while the speculum was imperfect. On 

 February 20, after it was in good order, a power of 470 showed 

 the stars quite distinct there on a resolvable ground ; and this 

 clearly separated into smaller stars with 830, which the instru- 

 ment bore with complete distinctness. This diffusion of so 

 many knots of stars through a vast stratum of others much 

 more minute is a most wonderful sight ; and while looking at 

 it he could not help speculating on the aspect which the hea- 

 vens would present to an observer there. Yet, possibly, the 

 Milky Way, if viewed from without, in the direction of Taurus, 

 would exhibit something similar. The Magellanic Clouds, 

 as described by Sir J. Herschel, are evidently analogous sys- 

 tems. On the same evening an eighth star was found in the 

 trapezium, a seventh having been discovered on the 10th; the 

 first near Herschel's a, and in the opposite direction from the 

 sixth one detected by Sir James South's large achromatic, and 

 more distant ; the second near j3. It is worth mentioning, as 

 illustrative of the effect of previous knowledge on vision, that 



* Phil. Trans. 1844, p. 322. 



