daily task, but it is plain that her mind was running on her comet.
August 2.—To-day I calculated one hundred and fifty nebulæ—I fear it will not be clear to-night, it has been raining throughout the whole day, but now seems to clear up a little. One o'clock: the object of last night is a comet.
Before going to bed that night she wrote to several of the principal astronomers to announce her discovery. To Dr. Blagden she says:—
The employment of writing down the observations when my brother uses the twenty-foot reflector, does not often allow me time to look at the heavens; but as he is now on a visit to Germany, I have taken the opportunity to sweep in the neighbourhood of the sun in search of comets, and last night I found an object very much resembling in colour and brightness the twenty-seven nebulæ of the "Connoissance des Temps," etc.
She then describes the position and appearance of the suspected comet, as she calls it, and adds that her observations were made with a Newtonian sweeper of twenty-seven-inch focal length, and a power of about twenty.
"Sweeping," which was such a delight to Miss Herschel, consists in directing the telescope to a given point in the heavens, and allowing it to remain in that position. By the motion of the earth, all stars situated on the parallel of declination (or distance from the equator) to which the instrument is directed pass across the field in their order of right ascension, and can be recognized by reference to a clock showing sidereal time. When any star or nebula is observed where, according to the catalogues, no star should be, it is noted for further investigation. In one of her letters, many years afterwards,[1] to Sir John Herschel, Miss Herschel mentions the contrivance by which she used to obtain the time. "You mention a monkey-clock, or jack, in your paper. I would only notice (if you mean the jack in the painted deal-case) that Alex made it merely to take with me on the roof when I was sweeping for comets, that I might count seconds by it, going softly downstairs till I was within hearing of the beat of the timepiece on the ground-floor (at that time our Observatory), all doors being open."
Miss Herschel's remark, that she was sweeping "in the neighbourhood of the sun," is possibly an error in the transcription of her letter. The sun had disappeared on the day in question by half past seven; and had that luminary been above the visible horizon, his rays would have prevented the comet from being observed if it had been anywhere in his vicinity. From Miss Herschel's description of the comet's position (in the constellation Comæ Bernices), it was on the day of the discovery about three hours later than the sun in right ascension, and therefore would pass the meridian about three o'clock in the day; at ten in the evening it would be in the north-western heavens, and not very far from the horizon. It is possible that this is what Miss Herschel means by "the neighbourhood of the sun."
The same post which conveyed her letter to Dr. Blagden took also one to her friend M. Aubert, who sent in reply a warm letter of congratulation:—
I wish you joy [he says] most sincerely on the discovery. I am more pleased than you can well conceive that you have made it, and I think I see your wonderfully clever and wonderfully amiable brother, upon the news of it, shed a tear of joy. You have immortalized your name, and you deserve such a reward from the Being who has ordered all these things to move as we find them for your assiduity in the business of astronomy, and for your love for so celebrated and so deserving a brother.
To any other woman such a success would have been a subject at least of some exaltation, but she had no thought for herself. On her brother's return she resumed her place as his humble and unknown assistant without a regret for the career of original distinction which she was foregoing. First and last, Caroline Herschel discovered eight comets. Her journals usually contain such an entry as this:—"August—, 2 A.M., discovered a comet;" and the letter-book of the next day contains transcripts of communications to the astronomers of her own and other nations, giving its declination and right ascension, and "commending it to their protection"—of her own labours or success never one solitary word. Many years afterwards she said, with characteristic modesty, that it was all chance; "I never called a comet mine till several post-days passed without any account of them coming to hand. And after all, it is only like the children's game, "Wer am ersten kick ruft, soll den Apfel haben."[2]
On the 8th of May, 1788, Sir William
