symbols. I am very glad to use them as conveniently indicating a conclusion which it may afterwards be possible to obtain by strictly logical methods; but until these logical methods shall have been discovered, I regard the result as requiring further demonstration." Here-we note a want of confidence in mathematical deduction which appears to have been characteristic of Airy and his generation of mathematicians.
In his first year Airy read Whewell's textbook on Mechanics, just published, the first innovation made in the Cambridge system of Physical Science for many years, and which made partial use of the differential notation (d). By the beginning of his second year he was so far advanced that he took two private pupils for instruction in mathematics—men of his own year. By this means he became able to defray all his expenses without help from his relatives. In his early career as a student he started the custom of keeping on his desk a quire of scribbling paper sewed together; and on the current quire everything was written—translations from the Greek, prose translations into Latin, mathematical problems, memoranda of every kind. These quires were carefully preserved. This habit of writing out everything made him an accurate and ready man, and placed him far ahead of his contemporaries in the college examinations. He adopted the rule of writing on his quire every day a translation into Latin of three or four sentences; this he did in preparation for the final University examinations. While he was an undergraduate Babbage's difference machine was much talked of: in his last undergraduate year (1822) Airy studied the subject and made a sketch of a computing machine. About the same time he prepared a paper on the construction of a reflecting telescope with silvered glass; a paper which brought him an introduction to Mr. (afterwards) Sir John Herschel, and Mr. (afterwards) Sir James South, two of the active astronomers of the day.
In Airy's time a candidate for B. A. was required to pass a University ordeal, which was a survival of the ancient system of examination. The candidate at the end of his second and third years was required to state three theses which he was
