Page:Popular Science Monthly Volume 39.djvu/589

Rh the south pole, the greater portion of it being covered several times; and they show the spectra as well as the positions of the stars. A large part of the charts and nearly all the spectra are unique, not having been photographed elsewhere. Much time has been devoted at the three stations of the observatory to visual observations of the colors and markings of the planet Mars. A number of the so-called canals were recognized, but only one of them was seen to be double. The best means of photographic enlargement of astronomical observations have been studied. Investigations have been conducted with regard to the meteorology of the globe, with particular reference to cloudiness and other phenomena affecting the choice of astronomical stations; the fundamental principles of astronomical photography; the great nebulous region of Orion; the best form of standard light, and other details of quantitative photographic work.

Extension of the English Coal-fields.—A discovery of coal has been made near Dover which promises to mark a new era in the industrial development of England. It is full of interest, not only from the commercial point of view, but also, as Prof. Boyd Dawkins, who had much to do with it, remarks, because it is the story of a scientific idea originated many years ago, taking root in the minds of geologists, developed into theory, and ultimately verified by facts. The physical identity of the coal-bearing districts of Somerset on the west with those of northern France and Belgium on the east was recognized by Buckland and Conybeare, as far back as 1826, as well as the fact that the coalmeasures lie buried partially under the newer rocks. Twenty-nine years later, Mr. Godwin Austen read a paper before the Geological Society of London on the possible extension of the coal-measures beneath the southeastern part of England, in which he set forth the facts in the geological structure of the country; whence he drew the conclusion that there are coal-fields beneath the Oölitic and Cretaceous rocks in the south of England, and that they are near enough to the surface along a certain line to be capable of being worked. He mentioned the Thames Valley and the Weald of Kent and Sussex as possible places where they might be discovered. An inquiry was made between 1866 and 1871 under an official commission, before which Godwin Austen testified. The report of this commission, drawn up by Prof. Prestwich, gave the evidence for and against the existence of the alleged coal-fields. The views of Godwin Austen were fortified by a large series of observations; and the conclusions were reached that coal-fields of the same kind and value as those of Somerset and of northern France and Belgium exist under the newer rocks of the south of England, and that the same measures which disappear in the west under the newer rocks of Somerset reappear in the east from underneath the newer rocks of the Continent. The Subwealden Exploration Committee bored for this coal at Netherfield, from 1871 till 1875, to a depth of 1,905 feet without finding encouragement to go further. In 1886 new borings were begun at Dover. They have been carried on till the present time, to the depth of 1,224 feet. The coal-measures were struck at a depth of 1,204 feet from the surface, and a seam of good blazing coal was met with twenty feet lower. This discovery, Prof. Dawkins says, "establishes the fact that, at a depth of about 1,204 feet from the surface, there is a coal-field lying buried under the newer deposits of southeastern England, and proves up to the hilt the truth of Godwin Austen's hypothesis after a lapse of thirty-five years. The question is finally settled so far as the purely geological and scientific side of it goes." The commercial value of the discovery is next to be estimated. A favorable prognostic is derived from the richness of the corresponding beds on the Continent. The depth is not too great for profitable working, for most of the important coal-pits in England are worked to a greater depth than this, and range to more than 2,800 feet; and one pit at Charleroi in Belgium is worked to a depth of 3,412 feet.

Permanent Value of the High-altitude Cure.—The acclimation of consumptives to the climate of Colorado, and the return of cured patients from high altitudes, were discussed at last year's meeting of the American Climatological Association, in Pueblo, Col. Dr. H. O. Dodge regarded the acclimation of the individual as consisting' in overcoming the conditions of altitude and low