Dr. Gould's account continues, "he was invited to propose a plan for an observatory in connection with the Philadelphia High School, an invitation which he accepted with eagerness. In accordance with his suggestion, the committee in charge of the school imported from Munich the excellent Fraunhofer equatorial and Ertel meridian circle which, in his hands and those of his accomplished brother, the present director of the observatory, have done so much for astronomy in America not merely by the number of observations made with them, but also by the incentive which they afforded to the lovers of astronomy in other parts of the country. It is unquestionable that in several instances they induced successful efforts for the procurement of similar and even superior apparatus elsewhere." The results of Walker's researches appeared from time to time in the publications of the American Philosophical Society and various journals. It was in 1841 that he may be said to have "earned his spurs" by a paper on the periodical meteors of August and November, which for many years remained the most important memoir on the subject that had appeared. From that time on he is to be ranked among scientific investigators.
In 1845 Mr. Walker's affairs underwent a revolution. Certain commercial operations turned out disastrously and entirely bereft him of means. The sense of defeat, the loss of luxuries at a time of life when habits have become fixed, together with anxiety for the future, made the blow a hard one. But it revealed to him, and to the world, the extent of his own scientific ability, and opened the way to higher intellectual gratifications, which he quickly learned to appreciate. The Secretary of the Navy offered him a position in the observatory at Washington which he at once accepted. Here, for the first time, the facilities which his special gifts required were at his disposal, and he immediately proceeded to make good use of them. After a short time he gave up his position at the observatory to accept the direction of the longitude department of the Coast Survey an office which he ably filled until his last illness.
Early in 1847, while engaged in researches upon the then newly discovered planet Neptune, he became convinced that a star observed by Lalande in May, 1795, must have been this planet. With the telescope of the Naval Observatory Prof. Hubbard confirmed this conjecture, and astronomers were thus furnished with an observation of Neptune made fifty-two years before, which afforded means for a most accurate determination of the planet's orbit. The American was none too soon to secure priority, for, quite independently, the same important fact was laboriously hunted down in Europe by Petersen only a few weeks later. Walker now attacked the problem of Neptune's orbit; Benjamin
