His 'Record of Observations made at the Mayport Observatory' contains beautiful colored sketches of Jupiter, Saturn, Venus, Mars, the Orion Nebula, of double stars and of 'Scenery on the Moon'; and in addition, data of a numerical character. These early drawings are characterized by the refined taste and skill so well known from his later professional work.
Keeler entered Johns Hopkins University late in 1877; and, following major courses in physics and German, he was graduated with the degree of A. B. in 1881. At the end of his freshman year he accompanied Professor Hastings, as a member of Professor Holden's party from the Naval Observatory, to observe the total solar eclipse of July 29, 1878, at Central City, Col. Although his part was the modest one of making a drawing of the corona, his written report on the work is a model scientific paper, and may be read with profit by visual observers of eclipses.
In the spring of 1881 Professor Langley, desiring an assistant in the Allegheny Observatory, requested the Johns Hopkins University to recommend a suitable man for the place. Keeler was named and accepted the appointment, beginning work at Allegheny several weeks before receiving his degree. I was speaking in June of this year (1900) with one of the physicists who had recommended Keeler for the Allegheny position, and the subject of this very appointment came up. "I told Professor Langley," said he, "that one of my strongest reasons for the recommendation is that Keeler doesn't claim to know everything." To the end of his life this charming trait remained unimpaired. It is to Keeler's credit that he largely defrayed his own expenses in college by acting as assistant to some of the lecturers in the experimental courses.
Professor Langley made his noted expedition to the summit of Mt. Whitney, Cal., in June-September, 1881, to determine the value of the 'Solar Constant.' Keeler accompanied the expedition in the capacity of assistant, and carried out his share of the program with skill and efficiency. Returning at once to Allegheny, his work until May, 1883, was closely related to the many problems arising from the Mt. Whitney expedition.
The year 1883-84 was devoted to study and travel abroad. The months of June, July and August, at Heidelberg, were given to the study of light and electricity under Quincke, chemistry under Bunsen, and integral calculus under Fuchs. In the winter semester in Berlin he heard the lectures on physics by Helmholtz and Kayser, on differential equations by Runge and on quarternions by Glan. His main investigation in the physical laboratory was on 'the absorption of radiant heat by carbon dioxide'—a problem suggested no doubt by his Mt. Whitney experiences.
From June, 1884, to April, 1886, Keeler again served as assistant in
