Page:Popular Science Monthly Volume 44.djvu/585

From Wikisource
Jump to navigation Jump to search
This page has been proofread, but needs to be validated.

that, regarding a plant or an animal as an organism, we concern ourselves primarily with its activities or its energies. These are naturally distinguishable into two kinds, according as we consider the action of the whole organism in its relation to the external world or to other organisms, or the action of the parts or organs in their relation to each other. This distinction has always existed, but has only lately come into such prominence that it divides biologists into two camps—those who make it their aim to investigate the action of the organism and its parts by the accepted methods of physics and chemistry; and those who interest themselves rather in considering the place which each organism occupies and the part it plays in the economy of Nature.


A Year's Work in Physics.—Among the notable papers of the year resulting from studies in physics, Mr. R. T. Glazebrook, sectional president in the British Association, mentioned Mr. E. R. Griffith's redetermination of the mechanical equivalent of heat—a work which it has taken five years to complete. With the exception of one group of experiments the results differ by less than one part in ten thousand. During his investigation Mr. Griffith proved an exact accordance between the scale of temperature as determined by comparing his platinum thermometer with the air thermometer made in 1890 by Callendar and himself, and that of the nitrogen thermometer of the Bureau International at Sèvres. Among other long investigations completed during the year was Rowland's Table of Standard Wave Lengths. The photographic map of the solar spectrum taken by Mr. Riggs with a Rowland grating was also finished. Lord Rayleigh's paper ou the Intensity of Light reflected from Water and Mercury at nearly perpendicular incidence, combined with the experiments on reflection from liquid surfaces in the neighborhood of the polarizing angle, establishes results of the utmost importance in optical theory. "There is," says Lord Rayleigh, "no experimental evidence against the rigorous application of Fresnel's formula—for the reflection of polarized light to the ideal case of an abrupt transition between two uniform transparent media." Prof. Dewar has continued his experiments on the liquefaction of oxygen and nitrogen on a large scale. To a physicist perhaps the most important results of the research are the discovery of the magnetic properties of liquid oxygen, and the proof of the fact that the resistance of certain pure metals vanishes at absolute zero. The last discovery is borne out by Griffiths and Callendar's experiments with their platinum thermometers. Mr. Williams's article on the Relation of the Dimensions of Physical Quantities to Directions in Space led to an interesting discussion.


The Polar Basin.—In his presidential address before the Geographical Section of the British Association Mr. Henry Seebohm, after stating that the foundation of all geography is exploration, and that its scientific study requires a knowledge of cartography and of meteorology or climatology, elaborated these subjects in detail, taking the polar basin as an example. There is, he said, only one polar basin; the relative distribution of land and water and the geographical distribution of light and heat in the arctic region are absolutely unique. In no other part of the world is a similar climate to be found. The distribution of land and water round the south pole is almost the converse of that round the north pole. In the one we have a mountain of snow and ice covering a lofty mass of congealed water surrounded by an ocean stretching away with very little interruption from land to the confines of the tropics. In the other we have a basin of water surrounding a comparatively flat plain of pack ice, some of which is probably permanent (the so called palæocrystic sea), but most of which is driven hither and thither in summer by winds and currents, and is walled in by continental and island barriers broken only by the narrow outlets of Bering Strait and Baffin's Bay, and the broader gulf which leads to the Atlantic Ocean, and even that interrupted by Iceland, Spitzbergen, and Franz Josef Land. If we assume that the unknown regions are principally sea, then the polar basin, including the area drained by all rivers flowing into the Arctic Sea, may be roughly estimated to contain about 14,000,000 square miles, of which half is land and half water. In the coldest part of the basin the land is either glacier or tundra,