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POPULAR BCIENCE MONTHLY. 



the crown of the old tree. There is such a 

 labyrinth of passages in the hollow cham- 

 bers 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 be- 

 fore a parliamentary commission of inquiry, 

 is declared to be sufficient to justify com- 

 plete 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 de- 

 scribe 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 prin- 

 ciples of erudition, memory, and imagination. 

 By imagination, corresponding to what psy- 

 chologists call visualization, they represent 

 to themselves as if they saw them the posi- 

 tions 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 ne- 

 cessary 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 recapitulat- 

 ing 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 memo- 

 ries the memory of position and the memo- 

 ry of recapitulation. The third element of 

 the play, erudition, comprehends the recent 

 memory of a game. The analysis of it fur- 

 nishes a good occasion for studying the true 

 character of what may be called the memory 

 of ideas, and the part which former recol- 

 lections play in the acquisition of new con- 

 ceptions. 



MINOR PARAGRAPHS. 



Experiments on the influence of music 

 upon respiration recorded by MM. Alfred 

 Binet and J. Courtier in the Annee Psycho- 

 logique for 1897 indicate that musical sounds, 

 chords, and music in general as a sensorial 

 excitation, independent of all suggested feel- 

 ings, provoke acceleration of respiration, in- 

 creasing 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 distinc- 

 tion between sad or solemn and lively music 

 appears to be for the most part wholly the- 

 oretical, and hardly squares with the com- 

 plexity of the musical emotions produced by 

 the melodies with the infinite shadings sug- 

 gested 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 be- 

 fore the vessel has leaked to a dangerous 

 extent. This quality is under investigation 

 by official commissions of some of the Euro- 

 pean 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 neighbor- 

 hood. Thus, while the jackdaw will sit on 

 any part from the buttresses to the vane of 

 a cathedral, the stork, the gull, the cormo- 

 rant, and the falcon always seem uneasy un- 

 less perched upon the summit of the build- 



