that capacity Flamsteed was able to render material assistance to Newton by providing him with the observations which his lunar theory required. John Flamsteed was born at Denby, in Derbyshire, on the 19th of August, 1646. His mother died when he was three years old, and the second wife, whom his father took three years later, only lived until Flamsteed was eight, there being also two younger sisters. In his boyhood the future astronomer tells us that he was very fond of those romances which affect boy's imagination, but as he writes, "At twelve years of age I left all the wild ones and betook myself to read the better sort of them, which, though they were not probable, yet carried no seeming impossibility in the picturing." By the time Flamsteed was fifteen years old he had embarked in still more serious work, for he had read Plutarch's "Lives," Tacitus' "Roman History," and many other books of a similar description. In 1661 he became ill with some serious rheumatic affection, which obliged him to be withdrawn from school. It was then for the first time that he received the rudiments of a scientific education. He had, however, attained his sixteenth year before he made any progress in arithmetic. He tells us how his father taught him "the doctrine of fractions," and "the golden rule of three"--lessons which he seemed to have learned easily and quickly. One of the books which he read at this time directed his attention to astronomical instruments, and he was thus led to construct for himself a quadrant, by which he could take some simple astronomical observations. He further calculated a table to give the sun's altitudes at different hours, and thus displayed those tastes for practical astronomy which he lived to develop so greatly. It appears that these scientific studies were discountenanced by his father, who designed that his son should follow a business career. Flamsteed's natural inclination, however, forced him to prosecute astronomical work, notwithstanding the impediments that lay in his path. Unfortunately, his constitutional delicacy seems to have increased, and he had just completed his eighteenth year, "when," to use his own words, "the winter came on and thrust me again into the chimney, whence the heat and the dryness of the preceding summer had happily once before withdrawn me. But, it not being a fit season for physic, it was thought fit to let me alone this winter, and try the skill of another physician on me in the spring." It appears that at this time a quack named Valentine Greatrackes, was reputed to have effected most astonishing cures in Ireland merely by the stroke of his hands, without the application of any medicine whatever. Flamsteed's father, despairing of any remedy for his son from the legitimate branch of the profession, despatched him to Ireland on August 26th, 1665, he being then, as recorded with astronomical accuracy, "nineteen years, six days, and eleven hours old." The young astronomer, accompanied by a friend, arrived on a Tuesday at Liverpool but the wind not being favourable, they remained there till the following Friday, when a shift of the wind to the east