Page:Popular Science Monthly Volume 50.djvu/858

836 particularly in the study of solar physics. "His first communication to the Royal Astronomical Society," says Nature, upon whose obituary notice of Father Perry we rely for most of our material, "indicates the policy he pursued to undertake no work which was a mere duplication of that done at other places." It appears, from a summary of his solar work during the ten preceding years, given at a lecture at the Royal Institution in May, 1889, that it was carried on by means of drawings and spectroscopic observations. "For the drawings an image of the sun ten inches and a half in diameter was projected on a sheet of drawing-paper affixed to a sketch board carried by the telescope, and all markings on the sun traced. The drawing finished, the chromosphere and prominences were examined with the spectroscope. About two hundred and fifty drawings were made every year from 1880. The results of these observations were published annually in a neat little volume, and in various publications." Regular observations of Jupiter's satellites and of comets were also made, and spectroscopic observations of comets and stars. In the year 1888, for instance, the chromosphere was completely examined on eighty-four days and partly on three other days. The Rev. Aloysius L. Cortie, S. J., in his biography of Father Perry (London, Catholic Truth Society), describes the work at Stonyhurst as having included the daily drawing of the sun when possible, the measurement of the depth of the chromosphere, the heights of prominences, and observations of sun-spot spectra—a programme which was faithfully adhered to up to the time of Father Perry's death. The drawings of the sun spots, as they appeared in the Memoirs of the Royal Astronomical Society, reproductions of two of which are given in Father Cortie's book, show how much can be effected by means of the pencil. The main object of making these drawings, which are of great importance and supplement the solar photographs, was to throw light upon the theories of the mode of formation of spots, and to find, if possible, the clew to the connection between terrestrial magnetism and solar activity.

Father Perry's industry and strict attention to his work of observation are further attested in his contributions to Nature and other journals. In Nature, the only journal of which we have complete files at hand, we find from one to three communications each in twenty-three of the forty volumes which were published previous to his death, recording phenomena of weather, magnetism, the aurora borealis, meteors, the sun, and earthquakes. The first volume, for instance, has a communication describing the cyclone of January 13, 1870, as it prevailed at Stonyhurst. In the third volume are letters speaking of his having missed on some observation a particular faint yellow line in the