Or wield the sceptre of the sage at will
(That mighty mace which bursts its way to light),
Soar as thou wilt!—or plunge—thy ardent mind
Darts on—but cannot leave our love behind.”
Of Hamilton’s abstruse invention, the method of “Quaternions” (here alluded to), Herschel was, from the first, an enthusiastic admirer. He characterised it in 1847 as “a perfect cornucopia, from which, turn it on which side you will, something rich and valuable is sure to drop out.” The “power and pregnancy” of the new calculus were supremely delightful to him, and he advised every mathematician to gain mastery over it as a “working tool.” As such it has not yet been brought into ordinary use, yet it remains in the armoury of science, ready for emergencies.
Miss Mitchell of Nantucket, the discoverer of a comet, and a professor of astronomy, published in 1889 (in the Century magazine) her reminiscences of a short stay at Collingwood in 1858. Her host “was at that time sixty-six, but he looked much older, being lame and much bent in his figure. His mind, nevertheless, was full of vigour. He was engaged in re-writing the ‘Outlines of Astronomy.’” “Sir John’s forehead,” she says, “was bold but retreating; his mouth was very good. He was quick in motion and in speech. He was remarkably a gentleman; more like a woman in the instinctive perception of the wants and wishes of a guest.”
“In the evening,” she relates, “we played with letters, putting out charades and riddles, and telling anecdotes, Sir John joining the family party and chatting away like the young people.” He propounded the question: If one human pair, living in the time of Cheops, had doubled, and their descendants likewise, once every thirty years, could the resulting population find room on the earth? The company thought not. “But if they stood closely, and others stood on their shoulders, man, woman, and child, how many layers would there be?” “Perhaps three,” replied Miss Mitchell. “How many feet of men?” he insisted. “Possibly thirty.” “Enough to reach to the moon,” said his daughter. “To the sun,” exclaimed another. “More, more!” cried Sir John, exulting in the general astonishment. “To Neptune,” was the next bid. “Now you burn,” he allowed. “Take one hundred times the distance of Neptune, and it is very near.” “That,” he added, “is my way of whitewashing war, pestilence, and famine.”
He further entertained his American guest with accounts of the paradoxical notions communicated to him by self-taught or would-be astronomers. One had inferred the non-existence of the moon from Herschel’s chapters on lunar physics and motions. Another enclosed half-a-crown for a horoscope. A third wrote, “Shall I marry, and have I seen her?” In reference to the efforts then being made to introduce decimal coinage into England, he remarked, “We stick to old ways, but we are not cemented to them.”
The portrait of Caroline Herschel, painted by Tielemann in 1829, which she herself declared to “look like life itself,” hung in the drawing-room. (It is that reproduced in this volume.) “You would say in looking at it,” Miss Mitchell wrote, ‘she must have been handsome when she was young.’ Her ruffled cap shades a mild face, whose blue eyes were even then full of animation. But it was merely the beauty of age.”
Herschel was no exception to the rule that astronomers love music and flowers. He was never tired of gardening, and—to quote James Nasmyth—“his mechanical and manipulative faculty enabled him to take a keen interest in all the technical arts which so materially aid in the progress of science.” The manufacture of specula naturally came home to him, and he watched with genuine pleasure Nasmyth’s grinding and polishing operations. He spent several days with him at Hammerfield in 1864. “Of all the scientific men I have had the happiness of meeting,” Nasmyth wrote in his “Autobiography,” “Sir John stands supremely at the head of the list. He combined profound knowledge with perfect humility. He was simple, earnest, and companionable. He was entirely free from assumptions of superiority, and, still learning, would listen attentively to the humblest student. He was ready to counsel and instruct, as well as to receive information.”