711 



SCIENTIFIC SIDE-LIGHTS 



try. In these mixtures the product partakes, 

 to a greater or less degree, of the character 

 of its constituents, which can be recognized 

 essentially unchanged in the new material, 

 but, in all instances of true chemical union 

 and decomposition, the qualities of the sub- 

 stances concerned in the process entirely 

 disappear, and wholly different substances, 

 with new qualities, appear in their place. 

 COOKE New Chemistry, lect. 5, p. 114. 

 (A., 1899.) 



3519. UNION, CLOSE, OF BODY 

 WITH MIND Bodily Processes Affected by 

 Sensations. Modern physiological psychol- 

 ogy emphasizes the wonderfully delicate way 

 in which the whole nervous mass responds 

 to the slightest phases of change in all forms 

 of excitation, with accompanying modifica- 

 tions of even the lowest possible phases of 

 conscious mental life. Haller, for example, 

 noticed that the noise from beating a drum 

 increased the flow of blood from an open 

 vein. Mosso observed that the approach of 

 a lamp toward a patient whose brain was 

 exposed increased the volume of the brain 

 substance. M. Payot claims to have seen 

 the passage of a cloud over the sun increase 

 the respiratory rhythm and pulse-rate of a 

 sleeping infant. M. Fere found that slight 

 sensations of sound and smell sometimes 

 affect a man's dynamometric force. Schiff 

 and Vulpian have observed the pupils of the 

 eyes dilate under the influence of various 

 forms of excitement. Experiments in reac- 

 tion-time show that increasing the intensity 

 of conscious states of sensation increases the 

 volume of the blood in the forearm and hand 

 with which the agent is reacting. LADD Psy- 

 chology, ch. 3, p. 48. (S., 1899.) 



3520. UNION OF DANGEROUS SUB- 

 STANCES IN SALT Combination Harmless 

 and Useful. It is a curious fact in Nature 

 that two such substances as chlorin and sodi- 

 um, both of them so difficult and dangerous 

 to handle, should unite together to form such 

 a useful and harmless compound as common 

 salt. The important element in bleaching- 

 powder is the chlorin which it contains. It 

 is extensively used in the manufacture of pa- 

 per and in all other materials where bleach- 

 ing is required. The object of combining it 

 with lime, forming a chlorid of lime, is sim- 

 ply to have a convenient method of holding 

 the chlorin in a safe and convenient manner 

 until it is needed for use. ELISHA GRAY 

 Nature's Miracles, vol. iii, ch. 26, p. 219. 

 (F. H. & H., 1900.) 



3521. UNION OF DISSIMILAR 



TRAITS A Butcher among Song-birds The 

 Shrike Hawk's Bill with Sparrow's Foot. 

 The marked difference in the temperament 

 of birds is emphasized by finding among 

 the song-birds, who feed on fruit, seeds, and 

 insects, a bird who in his position and 

 choice of food is truly hawklike. Shrikes 

 are solitary, never assembling in flocks or 

 associating with other birds. Their days 

 are days of waiting, varied by a pounce upon 



some unfortunate field-mouse, or dash into 

 a flock of unsuspecting sparrows. But while 

 they resemble the hawks in these respects, 

 their manner of capturing their prey differs 

 from that of their larger prototypes. The 

 shrike [or butcher-bird] has a hawk's bill, 

 but a sparrow's foot, and, lacking the pow- 

 erful talons which make so deadly a weapon, 

 he captures his prey with his strong mandi- 

 bles. Possibly it may be due to his compara- 

 tively weak feet that he pursues the singular 

 custom of impaling his prey on some thorn 

 or hanging it from a crotch, where he can 

 better dissect it. CHAPMAN Bird-Life, ch. 

 7, p. 218. (A., 1900.) 



3522. UNION OF LABOR AND ART 



Art here [in Italy] stood in close rela- 

 tion with manual labor, and the artist was 

 only distinguished from the manual laborer 

 by higher intellectual gifts. KAAT Leonar- 

 do da Vinci als Naturforscher. (Translated 

 for Scientific Side-Lights.) 



3523. UNION OF RIVERS Evils 

 Averted by Nature's Compensation Speed 

 of Current Increased with Volume. A ques- 

 tion naturally arises, How the more tranquil 

 rivers of the valleys and plains, flowing on 

 comparatively level ground, can remove the 

 prodigious burden which is discharged into 

 them by their numerous tributaries, and by 

 what means they are enabled to convey 

 the whole mass to the sea? If they had 

 not this removing' power their channels 

 would be annually choked up, and the val- 

 leys of the lower country and plains at the 

 base of mountain chains would be continual- 

 ly strewed over with fragments of rock a^d 

 sterile sand. But this evil is prevented by 

 a general law regulating the conduct of run- 

 ning water that two equal streams do not, 

 when united, occupy a bed of double surface. 

 Nay, the width of the principal river, after 

 the junction of a tributary, sometimes re- 

 mains the same as before, or is even less- 

 ened. The cause of this apparent paradox was 

 long ago explained by the Italian writers, 

 who had studied the confluence of the Po 

 and its feeders in the plains of Lombardy. 

 The addition of a smaller river augments 

 the velocity of the main stream, often in 

 the same proportion as it does the quantity 

 of water. Thus the Venetian branch of the 

 Po swallowed up the Ferranese branch and 

 that of Panaro without any enlargement 

 of its own dimensions. The cause of the 

 greater velocity is, first, that after the 

 union of two rivers the water, in place of 

 the friction of four shores, has only that of 

 t\vo to surmount ; secondly, because the 

 main body of the stream being farther dis- 

 tant from the banks, flows on with less in- 

 terruption; and lastly, because a greater 

 quantity of water, moving more swiftly, digs 

 deeper into the river's bed. By this beauti- 

 ful adjustment the water which drains the 

 interior country is made continually to oc- 

 cupy less room as it approaches the sea; 

 and thus the most valuable part of our con- 



