. Royal Astronomical Society. 307 



isting. This circumstance increases my inclination to put on record 

 a recent observation of a peculiarly satisfactory kind. 



September 7, 1843. — At Mr. Lassell's observatory, Starfield, near 

 Liverpool. The day had been cloudless and remarkably warm, the 

 maximum of the thermometer being 76° where all precautions had 

 been taken to keep it as cool as possible. In the evening the sky 

 was hazy and the stars dull. At about 9 p.m. Mr. Lassell turned 

 his equatorially mounted 9-foot Newtonian reflector, of 9 inches 

 aperture, upon Saturn, with a power of 200, and was electrified at 

 the beautifully sharp and distinct view of the planet presented to 

 him. Having applied as an eye-piece an achromatic lens (being the 

 object-glass of a microscope), which produced a power of 450 times, 

 Mr. Lassell examined the planet for a few minutes. I then took my 

 place at the telescope, and Mr. Lassell requested me to examine care- 

 fully the extremities of the ring, and say if I observed anything re- 

 markable. Having obtained a fine adjustment of the focus, I pre- 

 sently perceived the outer ring to be divided into two. This per- 

 fectly coincided with the impression Mr. Lassell had previously re- 

 ceived. For some minutes I scrutinized this interesting object, and 

 occasionally, for several seconds together, had by far the finest view 

 of Saturn that I was ever favoured with. The outline of the planet 

 was very hard and sharply defined with power 450 ; and the primary 

 division of the ring very black and steadily seen all round the south- 

 ern side. When this was most satisfactorily observed, a dark line was 

 pretty obvious on the outer ring. I was not only perfectly satisfied 

 of its existence, but had time during the best views carefully to es- 

 timate its breadth, in comparison with that of the division ordinarily 

 seen. The proportion appeared to me to be as one to three ; but 

 Mr. Lassell estimated it at scarcely one-third. It is certainly rather 

 outside the middle of the outer ring, and is broadest at the major axis, 

 being in this respect precisely similar to the primary division. It 

 was equally visible at both ends of the ring. 



For further satisfaction other eye-pieces were tried. A positive 

 double eye-tube, magnifying 400 times, came nearest to the achro- 

 matic lens in efficiency ; yet the latter gave the impression of equal 

 sharpness and light, with an increase of 50 in the power. With 

 400 the secondary division was perceptible during occasional best 

 views of the planet ; but no lower power displayed it at all, though 

 with them the usual features of Saturn were splendidly distinct. A 

 positive double eye-piece producing a power of 520 was also applied, 

 but by this time the state of the air had deteriorated ; and though 

 some confirmatory glimpses were obtained, the view was not so good 

 as with the achromatic lens. 



Neither Mr. Lassell nor myself obtained a single glimpse of any 

 further subdivisions of the ring. The shading of the interior edge 

 of the inner ring was very obvious, but no dark line was even sus- 

 pected in that situation. 



From my description of this splendid telescopic view of Saturn, 

 it will be seen that it was very similar to that depicted by Captain 

 Kater, in fig. 3 of his drawings of the planet, in vol. iv. part I of the 



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