703 



SCIENTIFIC SIDE-LIGHTS 



Trail si toriness 

 ree 



dows before it reached me. I stood in the 

 stateroom, looking in the direction of the 

 fire, so as to get a glimpse of it as we ran 

 by. The time that my face was exposed 

 was only a small fraction of a second, and 

 the heat had to come through the glass of 

 two windows some distance apart, and yet 

 my face was burned to redness. The glass 

 was not heated, but the sides of the cars 

 were burned into blisters. The one was a 

 transparent and the other an opaque sub- 

 stance. ELISHA GRAY Nature's Miracles, 

 vol. ii, ch. 23, p. 194. (F. H. & H., 1900.) 



3477. TRANSMISSION OF RE- 

 TRIEVER'S INSTINCT Heredity of Ac- 

 quired Characters. The fixed and deliber- 

 ate stand of the pointer has with propriety 

 been regarded as a mere modification of a 

 habit, which may have been useful to a wild 

 race accustomed to wind game, and steal 

 upon it by surprise, first pausing for an in- 

 stant in order to spring with unerring aim. 

 The faculty of the retriever, however, may 

 justly be regarded as more inexplicable and 

 less easily referable to the instinctive pas- 

 sions of the species. M. Majendie, says a 

 French writer in a recently published me- 

 moir, having learned that there was a race 

 of dogs in England which stopped and 

 brought back game of their own accord, pro- 

 cured a pair, and having obtained a whelp 

 from them, kept it constantly under his eyes 

 until he had an opportunity of assuring him- 

 self that, without having received any in- 

 struction, and on the very first day that it 

 was carried to the chase, it brought back 

 game with as much steadiness as dogs which 

 had been schooled into the same maneuver 

 by means of the whip and collar. [See HE- 

 REDITY OF ACQUIRED CHARACTERS.] LYELL 

 Principles of Geology, bk. iii, ch. 35, p. 594. 

 (A., 1854.) 



3478. TRANSPARENCY NEVER 

 PERFECT A Sufficient Depth of Water Ab- 

 sorbs All Light Increase of Quantity Re- 

 verses Result. All bodies, even the most 

 transparent, are more or less absorbent of 

 light. Take the ease of water: in small 

 quantities it does not sensibly affect light. 

 A glass cell of clear water interposed in the 

 track of our beam does not perceptibly 

 change any one of the colors of the spectrum 

 derived from the beam. Still absorption, 

 tho insensible, has here occurred, and to 

 render it sensible we have only to increase 

 the depth of the water through which the 

 light passes. Instead of a cell an inch thick 

 let us take a layer ten or fifteen feet thick; 

 the color of the water is then very evident. 

 By augmenting the thickness we absorb 

 more of the light, and by making the thick- 

 ness very great we absorb the light alto- 

 gether. Lampblack or pitch can do no more, 

 and the only difference between them and 

 water is that a very small depth in their 

 case suffices to extinguish all the light. 

 The difference between the highest known 



transparency and the highest known opac- 

 ity is one of degree merely. TYNDALL Lec- 

 tures on Light, lect. 1, p. 35. (A., 1898.) 



3479. TRANSPORTATION BY STA- 

 GES Nature's Ice-boats Locust-seeds Borne 

 on Wings of Wind. And the wind is sure 

 to come along, a slight breeze to-day tossing 

 the half-pod a few feet, leaving it perhaps 

 to be again and again moved farther for- 

 ward. The writer has seen these half- pods 

 [of the locust] transported by this means 

 more than a block. But many of the pods 

 stick to the limbs till winter comes. Then 

 a breeze tears off a few pods and they 

 fall on the snow, which has filled up all 

 the crevices in the grass and between the 

 dead leaves and rubbish. Each half-pod, 

 freighted with every other seed, is ad- 

 mirably constructed ; like an ice - boat, it 

 has a sail always spread to the breeze. In 

 this way there is often nothing to hinder 

 some of the seeds from going a mile or two 

 in a few minutes, now and then striking 

 some object which jars off a seed or two. 

 The seeds are very hard, and no doubt pur- 

 posely so, that they may not be eaten by in- 

 sects or birds; but once in moist soil the 

 covering slowly swells and decays, allowing 

 the young plant to escape. Thus the locust- 

 seeds are provided with neither legs, wings, 

 fins, nor do they advertise by brilliant hue 

 and sweet pulp ; but they travel in a way of 

 their own, which is literally on the wings 

 of the wind. BEAL Seed Dispersal, ch. 5, p. 

 36. (G. & Co., 1898.) 



3480. TRAVELING, THREE RAPID 



MODES OF Maximum Speed of Horse Near- 

 ly Reached Possibilities of the Bicycle. 

 It is a very interesting fact that three out 

 of the four methods of rapid locomotion we 

 now possess should have attained about the 

 same maximum speed. The racehorse, the 

 steamship, and the bicycle have each of them 

 reached thirty miles an hour. The horse is, 

 however, close upon, if it has not actually 

 attained, its utmost limits; the bicycle can 

 already beat the horse for long distances, 

 and will certainly go at higher speeds for 

 short ones; while the steamship will also 

 go much quicker, tho how much no one can 

 yet say. The greatest possibilities are with 

 the bicycle driven by electric power or 

 compressed air, by which means, on a near- 

 ly straight and fairly level asphalt track, 

 no doubt fifty miles an hour will soon be 

 reached. WALLACE The Wonderful Century, 

 ch. 1, p. 9. (D. M. & Co., 1899.) 



3481. TREE, LIMITED CORRE- 

 SPONDENCE OF, WITH ITS ENVIRON- 

 MENT Irresponsiveness Is Death. Different 

 organisms correspond with [their] environ- 

 ment in varying degrees of completeness or 

 incompleteness. At the bottom of the bio- 

 logical scale we find organisms which have 

 only the most limited correspondence with 

 their surroundings." A tree, for example, 

 corresponds with the soil about its stem, 



