Page:Popular Science Monthly Volume 42.djvu/301

Rh in solar radiation by the operation of the same causes that produce sun-spots do beyond doubt occur; and the sudden blazing out of new stars, like that in Auriga, are facts which suggest almost unlimited possibilities of the rejuvenescence of suns. It may well be that the Glacial period is a phenomenon attendant upon the decrepitude of the sun, and the first of a series whose second term may be nearer at hand than geologists or laymen have previously suspected.

Depth of the Atmosphere.—Calculations based on the observation of the refraction of light have caused it to be supposed that the air becomes so rare at the height of about sixty miles that that distance may be regarded as the limit to its sensible extent; but other calculations, made during the present century, of the distance from the earth at which meteors ignite, indicate that the atmosphere extends to upward of a hundred miles. The question is thus presented, says M. Forster, in a paper on the subject, whether the incandescence of these meteors is caused by the resistance of an earthly atmosphere—that is, of oxygen and nitrogen moving with the earth—or is developed in an interstellar atmosphere. The fact that the aurora borealis reaches heights of about four hundred miles tells in favor of the latter hypothesis. The orbits of some comets and the satellites of Jupiter are subject to changes which can be explained only by the action of a resisting medium, and it would be desirable to determine from solar analysis whether the medium in which the aurora exhibits itself is differently composed from our atmosphere, either of gases emanating from the sun or those produced by the explosion of meteoric bodies. The luminous clouds, of which Mr. O. Jesse has made a special study, are objects of great importance in the study of the circulation of the upper atmospheric strata.

Cyrus W. Field.—Mr. Cyrus W. Field, who died at his summer home near this city, July 12th, will be best remembered for his agency in the laying of the Atlantic cables, by which methods of communication and of transacting business between this country and Europe have been revolutionized. Without him they would not have been put in operation for many years later than they were, if at all.

Mr. Field was born in Stockbridge, Mass., in 1819, began his business life as a clerk in A. T. Stewart's store at one dollar a week, and at the end of his term of apprenticeship set up in business for himself as a junk-dealer and paper-maker. He became interested in submarine telegraphy in 1853, and induced a few capitalists to join with him in the Atlantic telegraph enterprise. After thirteen years of effort, fifty journeys across the Atlantic, and many failures, the lines were established, and Mr. Field received the honors that were his due. Several years afterward, Mr. Field engaged in the enterprise of building the elevated railroads in New York city, and materially contributed by his energy to their speedy completion.

National Characteristics in Science.—In his address before the Physical Section of the British Association Prof. Arthur Schuster spoke of the peculiarities possessed by each nation which make it better fitted than its neighbors to do some particular part of the work on which the progress of science depends. No country, for instance, has rivaled France in the domain of accurate measurement, with which the names of Regnault and Amagat are associated, and the International Bureau of Weights and Measures has its fitting home in Paris. The best work of the German universities seems to consist in the following up of some theory to its logical conclusions and submitting it to the test of experiment. The speaker doubted whether the efforts to transplant the research work of German universities into England will prove successful. Does it not seem well to let each country take that share of work for which the natural growth of its character and its educational establishment best adapt it? As far as the work of the Physical Section is concerned, the strongest domain of English students has been that of mathematical physics. Look at the work done in Great Britain during the last two centuries—the work not only in physics, but in astronomy, chemistry, and biology.

Cause of the Bursting of Peat-hogs.—The curious phenomena of the swelling and bursting of peat-bogs have been studied by Herr Klinge. They generally occur after heavy rains, and are preceded by detonations