storing, we have what is stated above, viz., that the total cost within 3 miles of the works is 1½d. per horse-power per hour. This quantity of electricity will produce a light, according to the amount of division, equivalent to from 5 to 30 gas burners, which is much cheaper than gas.--_Chemical News_. * * * * * PHYSICAL SCIENCE IN OUR COMMON SCHOOLS. [Footnote: Read before the State Normal Institute at Winona, Minnesota, April 28, 1881, by Clarence M. Boutelle, Professor of Mathematics and Physical Science in the State Normal School.] Very little, perhaps, which is new can be said regarding the teaching of physical science by the experimental method. Special schools for scientific education, with large and costly laboratories, are by no means few nor poorly attended; scientific books and periodicals are widely read; scientific lectures are popular. But, while in many schools of advanced grade, science is taught in a scientific way, in many others the work is confined to the mere study of books, and in only a few of our common district schools is it taught at all. I shall advocate, and I believe with good reason, the use of apparatus and experiments to supplement the knowledge gained from books in schools where books are used, the giving of lessons to younger children who do not use books, and the giving of these lessons to some extent in all our schools. And the facts which I have gathered together regarding the teaching of science will be used with all these ends in view. Physics--using the term in its broadest sense--has been defined as the science which has for its object the study of the material world, the phenomena which it presents to us, the laws which govern (or account for) these phenomena, and the applications which can be made of either classes of related phenomena, or of laws, to the wants of man. Thus broadly defined, physics would be one of two great subjects covering the whole domain of knowledge. The entire world of matter, as distinguished from the world of mind, would be presented to us in a comprehensive study of physics. I shall consider in this discussion only a limited part of this great subject. Phenomena modified by the action of the vital force, either in plants or in animals, will be excluded; I shall not, therefore, consider such subjects as botany or zoölogy. Geology and related branches will also be omitted by restricting our study to phenomena which take place in short, definite, measurable periods of time. And lastly, those subjects in which, as in astronomy, the phenomena take place beyond the control of student and teacher, and in which their repetition at pleasure is impossible, will not be considered. Natural philosophy, or physics, as this term is generally used, and chemistry, will, therefore, be the subjects which we will consider as sources from which to draw matter for lessons for the children in our schools.