Page:Popular Science Monthly Volume 34.djvu/733

Rh way a thick mass of intermingled soil and silk was formed. The only effort at nest-building which it made was a rude burrow against the side of the box. This burrow was entirely destitute of silken lining, although occasionally the opening would be over-spun with a thin sheet.

Origin of Archæan Graphite.—In a paper at the British Association on the origin of graphite in the archæan rocks, the Rev. A. Irving points out that the occurrence of carbon in late rocks as the result of plant-life is no argument to prove that the graphite of the archæan is of similar origin. Indeed, conditions were then so different that this mode of origin is extremely unlikely. Elementary carbon is produced in three ways: in pig-iron, by reduction of carbonic acid by alkali metals, and by contact action of heated surfaces on hydrocarbons. As hydrocarbons exist in the heads of comets, some method of origin like the last is far more probable than that the graphite should be phytogenic. The author thought that Möbius's investigations disproved the organic origin of eozoön; the iron oxides of the American archæan would come from the combustion of iron vapor in oxygen, while the unfossiliferous limestones of the archæan can be explained on purely chemical and physical principles.

The Country Schools of New York.—The State Superintendent of Public Instruction of New York, in his last report, draws an unpleasant picture of the condition of the rural schools. In them, he says, "the work done depends almost exclusively upon the character and capability of the teacher. There is no 'system' to fall back upon, no machine which will turn out passable work, whether or no. If the teacher is discerning and bright and enthusiastic, results will frequently be attained which surpass any accomplished in the great schools; if indifferent, the results are of no consequence. . . . All teachers are entitled to consideration, for their work is trying and exacting; but this is more strikingly so in the crossroads districts than elsewhere. Their pay is small. . . . Their work is not confined to a single grade; they must meet the requirements of all grades and all classes. They must lay out their own course of study, if they have any. Text-books are frequently antiquated; there is no uniformity, even in the same school, and frequently not in the same class, and the teacher finds it impossible to work improvement. The school is very likely maintained only twenty-eight weeks in the year, just long enough to share in the public moneys. Attendance is irregular. Trustees drive hard bargains, for the number of young persons who want the place is very large. Continual change in the teachers is the order of the day. The time of employment is but for a single term, and frequently the trustee undertakes to make it by the day or the week, in order that he may be free to effect a change at any time, or that he may withhold pay, in violation of the spirit and intent of the statute, for the week occupied in attendance upon a teachers' institute. Supervision amounts to little or nothing, for distances are great, during a good part of the year roads are impassable, and it is physically impossible for the commissioner, with generally more than one hundred schools under his charge, to visit each very frequently."

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 expenditure of 2,500,000,000 pounds of energy. Assuming an area of 100 miles square, with a mean depth of one mile, was thus in vibration at any one instant of time—which is not improbable, considering the known rate of transmission and the long duration of the earthquake—the amount of energy thus represented would be 25 X 10·12 foot-pounds. This energy might be generated by the fall, under the action of gravity, of a cube of rock 1,000 feet on each edge, the mass of which would be 75,000,000 tons, through a vertical distance of 166 feet." Also, assuming certain magnitudes, "I find the energy of a cubic mile of the Charleston earthquake,