It is gratifying to know that the beautiful Japan Rose—originally called Pautia, but changed to Hortensia by Jussieu—was named after this distinguished woman. It is also gratifying to be assured that her engrossing work in astronomy in no wise caused her to neglect her home duties or to lose that sweetness of character and delicacy of refinement for which she was noted before she entered upon the absorbing and taxing career of astronomical computer.
The wife of Lalande's nephew, Mme. Lefrançais de Lalande, proved herself in many respects a worthy successor of Mme. Lepaute. "My niece," writes her uncle, Jérôme Lalande, "aids her husband in his observations and draws conclusions from them by calculation. She has reduced the observations of ten thousand stars, and prepared a work of three hundred pages of horary tables—an immense work for her age and sex. They are incorporated in my Abrégé de Navigation.
"She is one of the rare women who have written scientific books. She has published tables for finding the time at sea by the altitude of the sun and stars. These tables were printed in 1791 by the order of the National Assembly.... In 1799 she published a catalogue of ten thousand stars, reduced and calculated."
This distinguished observer and computer had a daughter in whom her grand-uncle was particularly interested. "This daughter of astronomy," he tells us, "was born the twentieth of January, 1790, the day on which we at Paris saw for the first time the comet which Miss Caroline Herschel had just discovered. The child was accordingly named Caroline; her godfather was Delambre."
The discoverer of the comet referred to was, in many ways, a most remarkable woman. She was the sister of Sir William Herschel, the illustrious pioneer of modern physical astronomy and the virtual founder of sidereal science, as we know it to-day. She was also the aunt of Sir John Herschel, who was the only rival of his uncle, Sir William, as an explorer of the heavens.
But she was far more than a mere relative of these immortal leaders in astronomic science. She herself was an astronomer of distinction, and is known, in the annals of astronomy, as the discoverer of no fewer than eight comets. Great, however, as was her skill as an observer and computer, it was as her brother's assistant that she is entitled to the most distinction. Her affection for him was as unbounded as her devotion to his life work was abiding and productive of great results. For fifty years, after joining him in England—they both had been born and bred in Hanover—she was ever at his side, to assist him in his labors and to cheer him by her words of counsel and encouragement. She helped him to grind and polish the mirrors that were used in his epoch-making reflectors. This was a most arduous task; for, at that time, there was no machinery sufficiently exact for grinding specula, and, as a consequence, the work had all to be done by hand. So interested was the great astronomer in his work, when polishing his larger specula, that he forgot all about the passage of time, and on these occasions his sister was constantly obliged, as she herself informs us, "to feed him by putting the victuals by bits into his mouth by way of keeping him alive." When finishing his seven-foot reflector he was on one occasion found so intent on his work that "he had not taken his hands from it for sixteen hours together."
In our day, when all kinds of astronomical apparatus are made by machinery, it is difficult for us to realize what stupendous labor was required to produce those giant telescopes with which the Herschels made their great discoveries and by which they, at the same time, revolutionized the science of the stars. For they had not only to design and make the specula, but also the mountings of the mirrors as well. And, in order to obtain the money required for material and workmen, they were obliged to make telescopes for sale. This meant an immense loss of precious time that would otherwise have been devoted to the study of the heavens.
After long years of struggle, during which the devoted brother and sister overcame countless difficulties of every kind, their condition was somewhat ameliorated by financial aid from the government and by William's appointment to the position of astronomer royal with a salary of £200 a year. When Sir William Watson heard that this limited sum had been granted by George III to the discoverer of Georgium Sidus—the planet now known as Uranus—he exclaimed, "Never bought monarch honor so cheap."
Shortly afterwards Caroline was appointed as assistant to her brother at a salary of £50 a year. This we should now consider but a nominal sum, but she managed to live on it. When she received the first quarterly payment of twelve pounds she wrote in her memoirs, "It was the first money I ever in all my lifetime thought myself to be at liberty to spend to my liking." Her appointment as assistant to her brother is notable from the fact that she was the first woman in England, if not in the world, to hold such a position in the government service.
Miss Herschel held this official appointment until Sir William's death in 1822. When not acting as her brother's assistant or secretary, she devoted her time to what she quaintly called "minding the heavens." It was during this period that she made her most important discoveries. As assistant, however, to so indefatigable an observer as Sir William Herschel, she had but little time for sweeping the heavens, for, when at home, Sir William "was invariably accustomed to carry on his observations until day-break, circumstances permitting, without regard to seasons; it was the business of his assistant to note the clocks and to write down the observations from his dictations as they were made. Subsequently she assisted in the laborious numerical calculations and reductions, so that it was only during his absence 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 by her discovered, she detected several remarkable nebulæ and clusters of stars, previously unnoticed, especially the superb nebulæ 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.'"[145]