For several years he visited schools, colleges and teachers' institutes in Oxford, Lebanon, Cleveland and other cities, lecturing on his favorite branches of science. It had been his intention to popularize the science of physical astronomy by the publication of tracts or pamphlets. PUBLISHES PAMPHLETS. In the year 1856, at the request of teachers before whom he had lectured at the institutes, and with a view to popularize scientific knowledge, the Professor commenced the publication of pamphlets. The first number treated of "The Geological Agency of Water and Subterranean Forces." Only two of these pamphlets came into the possession of the administrator. One of them was a good-sized volume, as may be inferred from the following articles it contained: "The Influence of Magnitude on Stability." "The Doctrine of Gravitation." "Theory of Tides." "Effects of Tides." "Cases of Excessive Tidal Action and Planetary Instability." "The Rings of Saturn." "The Supposed Influence of Satellites in Preserving Planetary Rings." "Movements of Comets." "The Tails of Comets." "Mass and Density of Comets." "Cometary Catastrophes." "Phenomena Attending the Fall of Meteors." "The Origin of Solar and Meteoric Light." "Variable Stars and the Sun's Spots." "Temporary Stars." "Electrical Light and the Aurora Borealis." "Proof of the Stability of the Solar System," with an appendix. Some of these subjects had been treated of at greater length and published by American and British associations for the advancement of science. He sent to the British Association for the Advancement of Science: "Cases of Planetary Instability Indicated by the Appearance of Temporary Stars." "Appearance of Temporary Stars." Other papers appeared: "Note on the Sunspots," Philosophical Magazine for December, 1858. "On the Solar Spots and Variable Stars," idem, Vol. 15, p. 359. "Changes in the Conditions of Celestial Bodies," an essay. "The Origin of Worlds," Popular Science Monthly, May, 1879. "Planetary Rings and New Stars," Popular Science Monthly, February, 1879. "Astronomical History of Worlds," idem, September, 1878. "On the Stability of Satellites in Small Orbits and the Theory of Saturn's Rings," Philosophical Magazine, May, 1861. "On the Origin of the Asteroids." Contributed to the American Association for the Advancement of Science. "Static and Dynamic Stability in the Secondary Systems," Philosophical Magazine, December, 1861. "On Phenomena which May be Traced to the Presence of a Medium Pervading all Space," idem, May 11, 1861. The Professor contributed to other publications on both sides of the Atlantic, but as he failed to retain copies of the articles or of the magazines in which they were published, doubtless many papers of interest are among the number.