Page:Popular Science Monthly Volume 41.djvu/806

786 knowledge of the functions of the brain. Its career must somewhat resemble that of the art of medicine. There were great physicians before Harvey found a starting-point for scientific physiology; yet the debt of practical medicine to physiology is now well-nigh incalculable. So it will be with the art of teaching: noble work has been done for its advancement in entire ignorance of the organ whose best development it seeks; but now, since there is already a large and constantly increasing fund of knowledge concerning the working of the brain, teachers who are not bound to the traditions of the past, but are looking eagerly for every means of improving their art, will assuredly not fail to take advantage of the new knowledge.

The result must be an enormous gain for the children of the future.

influence of a total solar eclipse on air pressure has been deduced by Herr Steen from the comparison of the records of fourteen Norwegian ships between Panama and Madagascar, during the eclipse of August 29, 1885, four of the ships having been within the zone of totality and four others very near it. Two maxima of pressure, separated by a minimum, were revealed. The double wave is explained by Herr Steen by assuming that during a solar eclipse day is changed to night for a short time, and the transition is much like the ordinary change from day to night in the tropics, where the twilight is short. There the curve of air pressure has regularly a maximum about 10, some time after sunset, and a minimum about 4 , shortly before sunrise; while a second maximum appears about 4 A total solar eclipse would naturally act in a similar way.