The year 1860 found the Professor possessed of a valuable collection of books, the accumulation of ten or fifteen years, all showing the marks of wear, some of them besmeared with the drippings from his candle. Among them were works of some of the most prominent authors in branches of theoretical and practical science. Those of Laplace, Kepler, Tycho-Brahe, Leibnitz, Herschel, Newton and others, together with many pamphlets and periodicals, composed his library. He possessed a familiar knowledge of the German, French, Italian and Spanish languages, and of ancient Greek and Latin. Many of his papers appeared in the continental languages. It may be here stated that for the eminent astronomer, Laplace, as a scientist and writer, Prof. Vaughn entertained great respect, though he could not accept his nebular hypothesis, because important parts of it would not bear mathematical investigation. [The proof is in the papers in my possession.--N.] In an article of the Professor to the Popular Science Monthly (February, 1879) is a case of the kind, showing that the distinguished astronomer ignored his own famous theory. The article reads: "In endeavoring to account for the direct motion in secondary systems Laplace contends that, in consequence of friction the supposed primitive solar rings would have a greater velocity in their outer than in their inner zones. Now, if friction is to counteract to such an extent the normal effects of gravitation, it must be an eternal bar against the origin of worlds by nebulous dismemberment, and if the ring of attenuated matter were placed under the circumstances suggested by the eminent astronomer, it would be ultimately doomed, not to form a planet, but to coalesce with the immense spheroid of fiery vapor it was supposed to have environed." It is interesting to know that the theory of our Professor was the correct one, as proved by a recent discovery of Prof. James E. Keeler, astronomer of the Allegheny Observatory. As announced in a daily paper: "Prof. James E. Keeler, of the Allegheny Observatory, has made a wonderful discovery. It is a scientific and positive demonstration of the fact that the rings of Saturn are made up of many small bodies and that the satellites of the inner edge of the rings move faster than the outer." As to satellites, Prof. Vaughn, in the paper quoted, page 466, states: "The matter spread over the wide annular fields is ever urged by its own attraction to collect together and form satellites, which are ever destroyed by attractive disturbance of the primary, and have their parts scattered once more over a wide space." INSTALLED AS PROFESSOR OF CHEMISTRY. The Professor was elected to the chair of chemistry in the Cincinnati College of Medicine and Surgery in 1860, where he served with distinction for twelve years. His scholarly valedictory at that institution is one of the papers reserved for publication in his memoirs.