spectra, now in process of publication, which is of the first order of importance in statistical studies of stellar distribution with reference to spectral type, and in studying the relation of parallax and distance, proper motion, radial velocity and its variation to the spectral characteristics of the stars. Perrine of Cordova is now establishing on Sierra Chica about twenty-five miles southwest of Cordova, a great reflecting telescope comparable in size with the instruments of the northern hemisphere, for investigation of the southern nebulæ and clusters, and motions of the stars. The elevation of this new Argentine observatory will be 4,000 feet above sea level. Another observatory at mountain elevation and in a highly favorable climate is the Lowell Observatory, located at about 7,000 feet elevation at Flagstaff, Arizona. Many localities were visited and the atmosphere tested especially for steadiness, an optical quality very essential for research on the planetary surfaces. Mexico was one of these stations, but local air currents and changes of temperature there were such that good seeing was far from prevalent, as had been expected. At Flagstaff, on the other hand, conditions have been pretty uniformly good, and an enormous amount of work on the planet Mars has been accumulated and published. The first successful photographs of this planet were taken there in 1905, and Jupiter, Saturn, the zodiacal light and many other test objects have been photographed, which demonstrates the excellence of the site for astronomical research. Within recent years spectrum research by Slipher, especially on the nebulæ, has been added to the program, and the rotation and radial velocities of many nebulæ have been determined. On Mount Wilson, near Pasadena, California, at an elevation of nearly 6,000 feet, is the Carnegie Solar Observatory, founded and equipped under the direction of Professor George E. Hale, as a department of the Carnegie Institution of Washington, of which Dr. John Campbell Merriam is President. The climatology of the region was carefully investigated and tests of the seeing made by Hussey and others. Although equipped primarily for study of the sun, the program of the observatory has been widely amplified to include the stars and nebulæ. The instrumental equipment is unique in many respects. To avoid the harmful effect of unsteadiness of air strata close to the ground a tower 150 feet high was erected, with a dome surmounting it and covering a coelostat with mirror for reflecting the sun's rays vertically downward. Underneath the tower a dry well was excavated to a depth equal to 1/2 the height of the tower above it. In the subterranean chamber is the spectroheliograph of exceptional size and power. The sun's original image is nearly 17 inches in diameter on the plate, and the solar chromosphere and prominences, together with the photosphere and faculæ, are all recorded by monochromatic light.