Isolation 

 Knives 



SCIENTIFIC SIDE-LIGHTS 



864 



which animate them are of an order superior 

 to their respective attractions. FLAMMARI- 

 ON Popular Astronomy, bk. vi, ch. 5, p. 600. 

 (A.) 



1776. ISOLATION OF SEQUOIAS 

 Origin of the Redwood Mysterious. One 

 notable thing about the sequioa-trees is their 

 isolation. Most of the trees associated with 

 them are of peculiar species, and some of 

 them are nearly as local. Yet every pine, 

 fir, and cypress of California is in some 

 sort familiar, because it has near relatives 

 in other parts of the world. But the red- 

 woods have none. The redwood including 

 in that name the two species of " big trees " 

 belongs to the general cypress family, but 

 is sui generis. Thus isolated systematically, 

 and extremely isolated geographically, and 

 so wonderful in size and port, they more 

 than other trees suggest questions. GRAY 

 Darwiniana, art. 5, p. 208. (A., 1899.) 



1777. ISOLATION OF THE SOLAR 



SYSTEM Stellar Distances. The solar sys- 

 tem seems to us very vast, the abyss which 

 separates our world from Mars, Jupiter, 

 Saturn, and Neptune appears to us immense ; 

 relatively to the fixed stars, however, our 

 whole system represents but an isolated fam- 

 ily immediately surrounding us ; a sphere as 

 vast as the whole solar system would be 

 reduced to the size of a simple point if it 

 were transported to the distance of the 

 nearest star. The space which extends be- 

 tween the solar system and the stars, and 

 which separates the stars from each other, 

 seems to be entirely void of visible matter, 

 with the exception of nebulous fragments, 

 cometary or meteoric, which circulate here 

 and there in the immense voids. Nine thou- 

 sand two hundred and fifty systems like ours 

 (bounded by Neptune) would be contained 

 in the space which isolates us from the 

 nearest star! 



If a terrible explosion occurred in this 

 star, and if the sound could traverse the 

 void which separates it from us, this sound 

 would take more than three millions of years 

 to reach us. FLAMMARION Popular Astrono- 

 my, bk. vi, ch. 1, p. 553. (A.) 



1778. JOURNEY THROUGH TRACK- 

 LESS SPACE Migration of Oriole, and Bobo- 

 link. The oriole, who builds his swinging 

 nest in your elm-tree, will winter in Central 

 America; the bobolink, who seems so care- 

 free in your meadows, must journey to his 

 winter quarters in southern Brazil. But, 

 unless accident befalls, both birds will re- 

 turn to you the following spring. 'We are 

 so accustomed to these phenomena that we 

 accept them as part of the changing sea- 

 sons without realizing how wonderful they 

 are. But look for a moment at a map and 

 try to form a mental picture of the bobo- 

 link's route.^ Over valleys, mountains, 

 marshes, plains, and forests, over straits 

 and seas hundreds of miles in width, he 

 pursues a course through trackless space 

 with a regularity and certainty which bring 



him to the same place at nearly the same 

 time year after year. How much of hia 

 knowledge of the route he has inherited, 

 and how much learned during his own life- 

 time, is a question. CHAPMAN Bird-Life, ch. 

 4, p. 54. (A., 1900.) 



1779. JOY EXALTS AS GRIEF DE- 

 PRESSES Muscles, Arteries, and Nutrition 

 Affected by Mental States. The familiar ob- 

 servations first, that a lively hope or joy 

 exerts an enlivening effect upon the bodily 

 life, quiet and equable when moderate, but, 

 when stronger, evinced in the brilliancy of 

 the eye, in the quickened pulse and respira- 

 tion, in an inclination to laugh and sing; 

 and, secondly, that grief or other depressing 

 passion has an opposite effect, relaxing the 

 arteries, enfeebling the heart, making the eye 

 dull, impeding digestion, and producing an 

 inclination to sigh and weep these familiar 

 observations of opposite effects indicate the 

 large part which mental states may play, 

 not in the causation of all sorts of diseases 

 alone, but in aiding recovery from them. A 

 sudden and great mental shock may, like a 

 great physical shock, and perhaps in the 

 same way, paralyze for a time all the bodily 

 and mental functions, or cause instant death. 

 It may, again, produce epilepsy, apoplexy, 

 or insanity, while a prolonged state of de- 

 pression and anxiety is sometimes an im- 

 portant agent in the causation of chronic 

 disease, such as diabetes and heart-disease. 

 Can it be doubted, too, that the strong belief 

 that a bodily disorder will be cured by some 

 appliance, itself innocent of good or harm, 

 may so affect beneficially the nutrition of 

 the part as actually to effect a cure? To 

 me it seems not unreasonable to suppose 

 that the mind may stamp its tone, if not 

 its very features, on the individual elements 

 of the body, inspiring them with hope and 

 energy, or infecting them with despair and 

 feebleness. MATJDSLEY Body and Mind, lect. 

 1, p. 38. (A., 1898.) 



1780. JOY OF DISCOVERY There 



is a certain form of emotion called intel- 

 lectual pleasure which may be excited by 

 poetry, literature, Nature, or art. But F 

 doubt whether among the pleasures of the 

 intellect there is any more pure and con- 

 centrated than that experienced by the scien- 

 tific man when a difficulty which has chal- 

 lenged the human mind for ages melts be- 

 fore his eyes and recrystallizes as an il- 

 lustration of natural law. TYNDALL New 

 Fragments, p. 202. (A., 1897.) 



1781. JOY OR SORROW EXAGGER- 

 ATED IN MEMORY Minds Differ in Choice 

 of Images Retained. Besides the impossibil- 

 ity of getting at the average and prevailing 

 mental tone of a distant section of life, 

 there is a special difficulty in determining 

 the degree of happiness of the past, arising 

 from the fact that our memory for pleasures 

 and for pains may not be equally good. 

 Most people, perhaps, can recall the enjoy- 

 ments of the past much more vividly than 



