733 



SCIENTIFIC SIDE-LIGHTS 



Vegetation 

 Ventriloquh 



are compelled to raise their level. When- 

 ever this occurs their velocity is much in- 

 creased. The current which runs through 

 the Race of Alderney, between the island of 

 that name and the mainland, has a velocity 

 of about eight English miles an hour. Cap- 

 tain Hewett found that in the Pentland 

 Firth the stream, in ordinary spring tides, 

 runs ten miles and a half an hour, and 

 about thirteen miles during violent storms. 

 The greatest velocity of the tidal current 

 through the " Shoots " or New Passage, in 

 the Bristol Channel, is fourteen English 

 miles an hour ; and Captain King observed, 

 in his survey of the Straits of Magellan, that 

 the tide ran at the same rate through the 

 " First Narrows," and about eight geo- 

 graphical miles an hour in other parts of 

 those straits. LYELL Principles of Geology, 

 bk. ii, ch. 19, p. 293. (A., 1854.) 



3633. VELOCITY, UNIMAGINABLE, 

 OF ELECTRICITY Emblem of Speed of 

 Thought Moving Bodies Seen Motionless. 

 A flash of lightning cleaves a cloud, appear- 

 ing and disappearing in less than a hundred- 

 thousandth of a second, and the velocity of 

 electricity is such as would carry it in a 

 single second over a distance almost equal 

 to that which separates the earth and moon. 

 It is well known that a luminous impression 

 once made upon the retina endures for about 

 one-sixth of a second, and that this is the 

 reason why we see a continuous band of 

 light when a glowing coal is caused to pass 

 rapidly through the air. A body illumina- 

 ted by an instantaneous flash continues to 

 be seen for the sixth of a second after the 

 flash has become extinct; and if the body 

 thus illuminated be in motion, it appears 

 at rest at the place where the flash falls 

 upon it. When a color-top with differently 

 colored sectors is caused to spin rapidly the 

 colors blend together. Such a top, rotating 

 in a dark room and illuminated by an elec- 

 tric spark, appears motionless, each distinct 

 color being clearly seen. Professor Dove 

 has found that a flash of lightning produces 

 the same effect. During a thunder-storm he 

 put a color-top in exceedingly rapid motion, 

 and found that every flash revealed the top 

 as a motionless object, with its colors dis- 

 tinct. TYNDALL Fragments of Science, vol. 

 i, ch. 21, p. 440. (A., 1900.) 



3634. VENOM ADAPTED TO VIC- 

 TIM One Plan Must Comprehend Destroyer 

 and Destroyed. The poison of a deadly 

 snake let us for a moment consider what 

 this is. It is a secretion of definite chemical 

 properties which have reference, not only 

 not even mainly to the organism of the 

 animal in which it is developed, but specially 

 to the organism of another animal which it 

 is intended to destroy. Some naturalists 

 have a vague sort of notion that, as regards 

 merely mechanical weapons, or organs of 

 attack, they may be developed by use that 

 legs may become longer by fast running, 

 teeth sharper and longer by much biting. 



Be it so: this law of growth, if it exist, ia 

 but itself an instrument whereby purpose 

 is fulfilled. But how will this law of growth 

 adjust a poison in one animal with such 

 subtle knowledge of the organization of an- 

 other that the deadly virus shall in a few 

 minutes curdle the blood, benumb the nerves, 

 and rush in upon the citadel of life? There 

 is but one explanation a Mind, having mi- 

 nute and perfect knowledge of the structure 

 of both, has designed the one to be capable 

 of inflicting death upon the other. This 

 mental purpose and resolve is the one thing 

 which our intelligence perceives with direct 

 and intuitive recognition. The method of 

 creation, by means of which this purpose has 

 been carried into effect, is utterly unknown. 

 ARGYLL Reign of Law, oh. 1, p. 21. (Burt.) 



3635. VENTILATION IS LIFE Deadly 

 Products of Combustion Breathing Is Com- 

 bustion without Flame. We often take 

 great precautions to prevent its [carbon di- 

 oxid or carbonic acid] escape. Scared by the 

 ghosts of rheumatism and neuralgia, some 

 people in winter close the doors of* their 

 apartments and stop up every crevice by 

 which fresh air can enter or foul air escape. 



By means of a sandbag at the window, 

 another at the door, and a piece of list care- 

 fully tacked along its edge, the whole ar- 

 rangement being supplemented by a screen, 

 the products of combustion and exhalation 

 are kept circulating in the room and 

 breathed over and over again by those 

 within, at the cost of morning headache, 

 languor, and depression, with a long train 

 of other evils following in the wake. From 

 the fire, from the lights, and from the lungs 

 of the inmates, the poisonous gas is evolved, 

 and must be removed by efficient ventila- 

 tion. We are here struck by the remarkable 

 analogy between the process of combustion 

 and the function of respiration. 



The latter is, in fact, a species of com- 

 bustion without flame. The carbon of the 

 impure venous blood unites with the oxygen 

 of the air to form carbonic acid gas, while 

 the hydrogen unites with another portion 

 of oxygen to form water. Both products 

 are expelled at each exhalation, and the 

 chemical action going on within the body 

 raises its temperature to nearly 100. 

 LOWE Nature-Studies, p. 4. (Hum., 1888.) 



3636. VENTRILOQUISM IN NATU- 

 RAL MAGIC Judgment of Distance Relative. 

 A change of wind, an unusual stillness 

 in the air, is quite sufficient to produce the 

 sense that sounding objects are nearer than 

 they actually are. The art of the ventrilo- 

 quist manifestly aims at producing this kind 

 of illusion. By imitating the dull effect of 

 a distant voice, he is able to excite in the 

 minds of his audience a powerful conviction 

 that the sounds proceed from a distant 

 point. There is little doubt that ventrilo- 

 quism has played a conspicuous part in the 

 arts of divination and magic. SULLY Il- 

 lusions, ch. 5, p. 82. (A., 1897.) 



