duction by either of these ships on her next trip. Nearly equal speed has been made between England and Australia. At the beginning of the century this passage required eight months by sailing-vessels, and is now made by steamers in about six weeks. The Ormuz, launched in 1887, was designed to greatly reduce this time, and, although at first not realizing expectations, in October of the same year she exceeded them by covering the distance between London and Adelaide m a trifle under twenty-four days.
Colors of Flying-Squirrels.—A paper was read in the American Association, by Mr. W. E. Taylor, on color variations of Nebraska flying-squirrels. The American flying-squirrel presents a range of geographical variation in size quite unparalleled in other members of the Sciuridæ. On the other hand, the coloration is remarkably constant. The local variations in color were illustrated by descriptions and comparisons of five specimens examined by the writer, all collected near the Missouri River, in Nebraska, at different times and places. The writer concludes: 1. That the measurements correspond to the Northern variety, while the colors correspond more nearly with the Southern varieties. 2. Local variations in color are great, these variations existing in members of the same nest. 3. Locally, at least, the two varieties appear to grade into each other. 4. The degree of coloration on some parts of different specimens does not vary in the same rate.
Value of Experimental Psychology.—Pointing out the advantages of the experimental method of psychological investigation, combined with the introspective, Dr. J. McK. Cattell, of the University of Pennsylvania, says: "Experiment is not meant to take the place of introspection, but is meant to make scientific introspection possible. The study of consciousness is, as we all know, fraught with peculiar difficulties. It is not easy to be at once the observer and the observed. The eye sees not itself, and the phenomena are both complex and transient. The best results have been obtained when introspection has been combined with the study of the objective manifestations of the contents of other minds, more especially when these have on the one hand become fossilized, as in language, customs, art, etc., or, on the other hand, are relatively simple, as in children, in savages, and in disease; but, under circumstances the most favorable to scientific observation, there are serious difficulties in the way of exact observation and measurement, and it will be found in psychology, as elsewhere in science, that experiment gives the most trustworthy and accurate results. Experiment calls up the phenomena to be studied when wanted, and by keeping certain conditions constant and by altering others gives the best chance for analysis; above all, it enables us to photograph the transient phenomena and subject them to objective examination and measurement."
Continental Centers.—The orographic centers of the several continents have been graphically determined by M. A. de Tillo as follows:
| CONTINENTS. | Latitude. | Longitude (from Greenwich). |
| Asia, with Europe | 43° N. | 85° E. |
| Africa | 4° N. | 127° E. |
| North America | 45° N. | 102° W. |
| South America | 14° S. | 50° W. |
These four centers form a fairly regular quadrilateral. The longest side (92°) is the one between the Asiatic and North American centers. The African center is distant 82° from the South American center. It is worthy of remark that the distance between the centers of the double continents is approximately the same, the center of Asia being 70° from that of Africa, while the centers of the double American continent are separated by 73°. The geometric center of the four continents is in the region of the Azores and the Canaries.
The Energy in an Earthquake.—After explaining, in the American Association, the impossibility of calculating the intensity of an earthquake more than approximately, Prof. T. C. Mendenhall applied a formula to determine the energy involved in the Japanese earthquake of January 15, 1887, which disturbed over 30,000 square miles of territory. He said: "Assuming a mass of 150 pounds per cubic feet, and taking a cubic mile as the volume to be considered, I find that to put it in vibration required the
