Memoir and Correspondence of Caroline Herschel

by Mrs. John Herschel

1822. Retrospection.

While they toiled together through those first ten years of ever-deepening interest and marvellous activity, during which the rapid juxtaposition of mirror-grinding, concerts, oratorios, music lessons,[^[30]] and frequent papers written for philosophical societies, almost takes the breath away as we read,—the brother had abundant opportunity of learning how far he could trust to his companion’s readiness, as well as capability, to accept of duties as utterly remote from all that her previous life had prepared her for as if he had asked her to accompany him on a pilgrimage to Mecca. And thus, of all of whom he had made trial, it was not the brilliant Jacob, nor the gifted Alexander, but the little quiet, home-bred Caroline, of whom nothing had been expected but to be up early and to do the work of the house, and to devote her leisure to knitting and sewing, in whom he found that steady devotion to a fixed purpose which he felt it was possible to link with his own. “I did nothing for my brother,” she said, “but what a well-trained puppy-dog would have done: that is to say, I did what he commanded me. I was a mere tool which he had the trouble of sharpening.” Such was always her own modest self-estimate. It is hardly too much to say that, to have worked as she had worked, and to have done all that she had accomplished, and to claim no more than the credit due to passive obedience to orders, is a depth of humility of that rare and noble kind which is in itself a form of greatness. It must not be forgotten, that the progress of astronomical science since Sir William Herschel’s great reflector startled the world, has not been greater than has been the change, both in opinion and practice, on the subject of female employments and education. The appointment of a young woman as an assistant astronomer, with a regular salary for her services, was an unprecedented occurrence in England. She had watched and shared in every effort and every failure from the first seven-foot telescope to the construction of the ponderous machinery that was to support the mighty tube of which she herself made the first crude model in pasteboard. When, finally, her brother was summoned to the King, and wrote to tell her how he fared at Court, she accepted the decision, by which he exchanged a handsome income for the sake of obtaining the command of his own time, and £200 a-year from his gracious sovereign, with only a passing expression of regret from the housekeeper’s point of view, and threw herself heart and soul into the new life at Datchet. One all-sufficing reward sweetened her labours—“I had the comfort to see that my brother was satisfied with my endeavours in assisting him.” When the dignity of original discovery gave her a distinct and separate claim to the respect of the astronomical world, she must have found out that she was something better than a mere tool. The requisite knowledge of algebra and mathematical formulæ for calculations and reductions she had to gather when and how she could: chiefly at meals, and at any odd moments when her brother could be asked questions, and the answers were carefully entered in her Commonplace Book, where examples of taking equal altitudes, and how to convert sidereal time into mean time, follow upon pages of problems, oblique plain triangles, right-angled spherical triangles, how to find the logarithm of a number given, and theorems for making tables of motion. With this slender store of attainment she accomplished a vast amount of valuable work, besides the regular duties of assistant to so indefatigable an observer as Sir William Herschel. He was invariably accustomed to carry on his telescopic observations till daybreak, circumstances permitting, without any regard to season; it was the business of his assistant to note the clocks and to write down the observations from his dictation as they were made. Subsequently she assisted in the laborious numerical calculations and reductions, so that it was only during his absences from home, or when any other interruption of his regular course of observation occurred, that she was able to devote herself to the Newtonian sweeper, which she used to such good purpose. Besides the eight comets discovered by her, she detected several remarkable nebulæ and clusters of stars previously unnoticed, especially the superb nebula known as No. 1, Class V., in Sir William Herschel’s Catalogue. Long practice taught her to make light of her work. “An observer at your twenty-foot when sweeping,” she wrote many years after, “wants nothing but a being who can and will execute his commands with the quickness of lightning; for you will have seen that in many sweeps six or twice six objects have been secured and described in one minute of time.”

The ten years from 1788 to 1798, although a blank as regards her personal history—the Recollections cease with her brother’s marriage—were among the busiest of her life, and in the year last mentioned the Royal Society published two of her works, namely, “A Catalogue of 860 Stars observed by Flamsteed, but not included in the British Catalogue,” and “A General Index of Reference to every Observation of every Star in the above-mentioned British Catalogue.” It is in reference to these that she wrote the very interesting letter to the Astronomer Royal, which is given among others, in its place, in the Journal. But another work, which was not published, was the most valuable, as it was the most laborious of all her undertakings. This was “The Reduction and Arrangement in the form of a Catalogue, in Zones, of all the Star-clusters and Nebulæ observed by Sir W. Herschel in his Sweeps.” It supplied the needful data for Sir John Herschel when he undertook the review of the nebulæ of the northern hemisphere; and it was for this that the Gold Medal of the Royal Astronomical Society was voted to her in 1828, followed by the extraordinary distinction of an Honorary Membership. This Catalogue was not completed until after her return to Hanover, and Sir David Brewster wrote of it as “a work of immense labour,” and “an extraordinary monument of the unextinguished ardour of a lady of seventy-five in the cause of abstract science.”

Her Sweepings.

Although the Recollections cease in 1788, there are some volumes recording the nature and results of her nightly “sweepings,” which Miss Herschel kept very regularly, and, as an unique example of a lady’s journal, a few of the entries may be of interest.

1788. Sept. 9th.—My brother showed me the five satellites of Saturn. He made me take notice of a star, which made a double star last night with the fifth satellite.

* * * * *

Dec. 8th.—I swept for a comet which was announced in the papers as having been discovered the 26th of November by Mr. Messier. According to the observations of that date, it should have been within a few degrees of the Pole star (by my brother’s calculation), but though I swept with great attention a space of at least ten or twelve degrees all around the pole over repeatedly, I could find nothing.

Another night of unavailing search, with thermometer 20°.[^[31]]

1790. Jan. 7th.—I have swept all this evening for my [third] comet in vain. My brother showed me the G. Sidus in the twenty-foot telescope, and I saw both its satellites very plainly.