dotted with extremely minute craters, and two black parallel 

 stripes in the bottom of Aristarchus. 



The Georgian was the only planet visible ; its disc did 

 not show any trace of a ring. As to its satellites, it is diffi- 

 cult to pronounce whether the luminous points seen near it 

 are satellites or stars, without micrometer measures. On 

 October 29, three such points were seen within a few 

 seconds of the planet, which were not visible on November 

 5; but then two others were to be traced, one of which could 

 not have been overlooked in the first instance, had it been 

 in the same position. If these were satellites, as is not im- 

 probable, there would be no great difficulty in taking good 

 measurement both of their distance and position. 



There could be little doubt of the high illuminating 

 power of such a telescope, yet an example or two may be 

 desirable. Between e^ and e^ Lyrae, there are two faint 

 stars, which Sir J. Herschel (Phil. Trans. 1824) calls "de- 

 bilissima," and which seem to have been, at that time, the 

 only set visible in the twenty-feet reflector. These, at the 

 altitude of 18° were visible without an eye-glass, and also 

 when the aperture was contracted to twelve inches. With 

 an aperture of eighteen inches, power 600, they and two 

 other stars (seen in Mr. Cooper's achromatic of 13-2 aper- 

 ture, and the Armagh reflector of 15) are easily seen. 

 With the whole aperture, a fifth is visible, which Dr. R. 

 had not before noticed. Nov. 5th, strong moonlight. 



In the nebula of Orion, the fifth star of the trapezium 

 is easily seen with either speculum, even when the aperture 

 is contracted to eighteen inches. The divided speculum 

 will not shew the sixth with the whole aperture, on account 

 of that sort of disintegration of large stars already noticed, 

 but does, in favourable moments, when contracted to 

 eighteen inches. With the solid mirror and whole aperture, 

 it stands out conspicuously under all the powers up to 1000, 



