Page:Memoir and correspondence of Caroline Herschel (1876).djvu/103

Rh an account of your discovery of a second comet on the 21st, and recommending it to my attention.

I received it only on the 24th, at ten in the morning, owing to the slowness of our penny post. I delayed acknowledging it till I could inform you at the same time I had seen it. The frost, unfortunately for us astronomers, broke up the very same morning that your letter arrived, in consequence of which the weather has been so bad that I could not get a sight of your comet till last night, the 26th, when, at 6h 34', it followed α Lyræ in the A. R., 3' 7" of time, and was 2° 30' S. of it. This only by the divisions of the equatorial and meridian circles, but true to a minute or two of declination and five seconds of time. I compared it more accurately with a small telescopic star nearer it, which, when settled hereafter, will determine its place within 30" of a degree. Hence its A. R. was about 18h 33' 55", and distance from the North Pole 53° 59'. By your observation of December 22nd, 5h 31' in the morning, its A. R. was 18h 35' 12", and P. D. 56° 56'. Hence it has moved retrograde in A. R. about the rate of 17' of time per day, and 30' per day northward in declination, which agrees nearly with your observation of its approach towards δ Lyræ. Its motion is fortunately favourable for our keeping sight of it for some time, which may be very useful, especially if it should be moving from us, which there is an equal chance for, as the contrary. It appeared to me very faint, and rather small, but the air was hazy. By its faintness and slow motion, it is probably at a considerable distance from the earth. Time will explain these things. Let us hope the best, and that it is approaching the earth to please and instruct us, and not to destroy us, for true astronomers have no fears of that kind. Witness Sir Harry Englefield's valuable tables of the apparent places of the Comet of 1661, expected to return at this time, with a delineation of its