“Come forth, O man, yon azure round survey, And view those lamps that yield eternal day; Bring forth your glasses; clear thy wondering eyes, Millions beyond the former millions rise; Look farther—millions more blaze from remoter skies.”
Sir William Herschel assuming that the instrument which he used could enable him to penetrate 497 times farther than Sirius, reckoned 116,000 stars to pass in a quarter of an hour, over the field of view, which subtended an angle of only 15′. If from such a narrow zone we compute, the whole celestial vault must display, within the range of telescopic vision, the stupendous number of more than five billions of stars. If each of these be the sun to a system similar to ours, and if the same number of planets revolve round it, then the whole planets in the universe will be more than fifty-five billions, not reckoning the satellites, which may be even more numerous. That part of the science which gives a description of the motions, figures, periods of revolution, and other phenomena of the celestial bodies, is called _descriptive astronomy_; that part which determines the motions, figures, periodical revolutions, distances, etc., of these orbs, is called _practical astronomy_; and that part which explains the causes of their motions, and demonstrates the laws by which those causes operate, is termed _physical astronomy_.
On the 16th of March, 1750, Caroline Lucretia Herschel was born. Her birthplace was Hanover. She was the fourth daughter of Isaac Herschel, and Ann Ilse Moritzen, his wife. Her parents had also six sons. The childhood of this distinguished woman is to us a blank. Till her twenty-second year, she lived in her native place; and her father and mother seem to have been anxious about her education, but their means were limited; and moreover, Hanover, during the latter end of the last century, did not possess the facilities for the acquirement of literature, science, and art, that it does now. Since 1837, when it became a royal residence, many changes have taken place, and numerous improvements continue to be made. We may therefore consistently affirm, that among the female examples of the pursuit of knowledge under difficulties, few deserve a higher place than Miss Herschel.
