he had access to a public library, where he studied more books on astronomy, and also Vince's Fluxions, then the principal testbook at Cambridge on the higher mathematics. Thus early was he introduced to Newton's methods. While at this school he watched for three weeks for a predicted return of Encke's comet; at last he saw it (1835) and he wrote home, "You may conceive with what pleasure I viewed this, the first comet which I had ever had a sight of, which at its visit 380 years ago threw all Europe into consternation, but now affords the highest pleasure to astronomers by proving the accuracy of their calculations and predictions." The following year an annular eclipse of the Sun took place. For the people on the farm he made a calculation of the times of the eclipse for that meridian and latitude, and also a diagram of the eclipse as it would appear to them. Next year his account of observations of an eclipse appeared in the London papers. He was now 18 years old; and had shown such signs of mathematical power that preparations were made to send him to Cambridge.
In 1839, when 20 years old, he entered St. John's College; while an undergraduate he was invariably the first man of his year in the college examinations. It was his custom to keep a memorandum book, in which at the end of his second college year (July 3, 1841) he made the following entry: "Formed a design, in the beginning of this week, of investigating as soon as possible after taking my degree, the irregularities in the motion of Uranus, which are yet unaccounted for, in order to find whether they may be attributed to the action of an undiscovered planet beyond it; and if possible thence to determine the elements of its orbit, etc., approximately, which would probably lead to its discovery." His attention had been drawn to the phenomenon by reading Airy's report on Astronomy to the British Association (1831-2); but no explanation is suggested there. Meanwhile he kept to the beaten path of training for the Tripos; as a result in 1843 he won the first place in that examination, the first Smith's prize and a fellowship from his college. After taking his degree, Adams attempted a first solution of his problem on the assumption that the orbit
