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Page:Popular Science Monthly Volume 51.djvu/588

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POPULAR SCIENCE MONTHLY.

the crown of the old tree. There is such a labyrinth of passages in the hollow chambers that to find the nest is not easy, even when the place of the bird's exit is marked." The testimony to the service rendered by the owls during the vole plague, given before a parliamentary commission of inquiry, is declared to be sufficient to justify complete protection of them by law.

 

Chess Players' Vision.—The study of the psychology of the great chess players has given Prof. Alfred Binet opportunity to describe a special form of visual memory which he calls geometrical. As represented by the players, the elements of blindfold chess playing are reducible to the three principles of erudition, memory, and imagination. By imagination, corresponding to what psychologists call visualization, they represent to themselves as if they saw them the positions of the pieces on the board. It is not an uncommon faculty, but is developed to a rarely high degree in the chess player; and has the peculiar power of abstracting from the object visualized solely the qualities necessary for the combinations of the game, consisting of the reciprocal positions of the pieces and their motions. The image seen by the player is therefore an image of fixed positions and possible movements; or, a geometrical visual image. A second element of blindfold chess playing is the recapitulating memory, or the faculty of repeating all the movements in the order in which they have been played. Blindfold playing rests chiefly on the exercise of these two memories—the memory of position and the memory of recapitulation. The third element of the play, erudition, comprehends the recent memory of a game. The analysis of it furnishes a good occasion for studying the true character of what may be called the memory of ideas, and the part which former recollections play in the acquisition of new conceptions.


MINOR PARAGRAPHS.

Experiments on the influence of music upon respiration recorded by MM. Alfred Binet and J. Courtier in the Année Psychologique for 1897 indicate that musical sounds, chords, and music in general as a sensorial excitation, independent of all suggested feelings, provoke acceleration of respiration, increasing as the movement is more lively, without disturbing the regularity of the breathing or augmenting its amplitude. The major mode is more exciting than the minor. The heart is similarly affected. The distinction between sad or solemn and lively music appears to be for the most part wholly theoretical, and hardly squares with the complexity of the musical emotions produced by the melodies with the infinite shadings suggested by the ideas of the libretto. The authors, however, infer from their researches that the acceleration of the heart and of respiration was not so marked during the hearing of sad pieces as in those in which joy and high excitation of musical emotions prevail.

A novel use is proposed for the pith of cornstalks as a packing between the inner and outer shell of war vessels. When pierced with a projectile it will absorb water and swell so rapidly as to close the opening before the vessel has leaked to a dangerous extent. This quality is under investigation by official commissions of some of the European nations. The by-product of the process of preparation seems to be equally valuable. The outer rim of the stalk ground up is found to make a fine and palatable food for cattle and horses. It is said to compare favorably too with the corn blades, timothy hay, and wheat bran. It also keeps well, and can be uniformly mixed with any ground grain.

Marked preferences for different kinds and altitudes of perching places are shown by different birds. The domesticated pigeon perches almost exclusively on buildings; in fact, the seldom flying domestic fowl takes oftener to trees. Wild pigeons, of course, must needs perch in trees. The Spectator calls attention to the fact that some species are never satisfied unless they occupy the absolutely highest point in the neighborhood. Thus, while the jackdaw will sit on any part from the buttresses to the vane of a cathedral, the stork, the gull, the cormorant, and the falcon always seem uneasy unless perched upon the summit of the build-