arity 



SCIENTIFIC SIDE-LIGHTS 



628 



a new law is the discovery of a similarity 

 which has hitherto been concealed in the 

 course of natural processes. It is a mani- 

 festation of that which our forefathers in a 

 serious sense described as " wit " ; it is of 

 the same quality as the highest perform- 

 ances of artistic perception in the discovery 

 of new types of expression. It is something 

 which cannot be forced, and which cannot 

 be acquired by any known method. Hence 

 all those aspire after it who wish to pass as 

 the faroied children of genius. It seems, 

 too, so easy, so free from trouble, to get by 

 sudden mental flashes an unattainable ad- 

 vantage over our contemporaries. The true 

 artist and the true inquirer know that 

 great works can only be produced by hard 

 work. HELMHOLTZ Popular Lectures, lect. 

 5, p. 227. (L. G. & Co., 1898.) 



30 1O. SIMPLICITY OF METHOD 



Opens Way to Marvelous Result Magnet- 

 ism Converted into Electric Light Fara- 

 day's Experiment. In the fall of 1831, 

 Professor Faraday announced that from a 

 magnet he had obtained electricity. On the 

 8th of February, 1832, he entered in his note- 

 book : " This evening, at Woolwich, experi- 

 mented with magnet, and for the first time 

 got the magnetic spark myself. . .'._." 



Next day he repeated this experiment, 

 and then, as was his habit, invited some of 

 his friends to see the new light. He had a 

 piece of soft iron, surrounded by coils of 

 wire insulated with calico and tied by com- 

 mon string. When he touched the pole of a 

 magnet with the soft iron, the ends of the 

 coil, as he says, opened a little, and a spark 

 passed between them. An electrical current 

 had been caused in the coil. PARK BENJA- 

 MIN Age of Electricity, ch. 7, p. 88. (S., 

 1897.) 



3111. SIMPLICITY OF SCIENTIFIC 

 DISCOVERY Forms of Leaves Modified by 

 Environment. In the year 1851, during a 

 country ramble in which the structures of 

 plants had been a topic of conversation with 

 a friend Mr. G. H. Lewes I happened to 

 pick up the leaf of a buttercup, and, draw- 

 ing it by its footstalk through my fingers 

 so as to thrust together its deeply cleft divi- 

 sions, observed that its palmate and almost 

 radial form was changed into a bilateral 

 one; and that were the divisions to grow 

 together in this new position, an ordinary 

 bilateral leaf would result. Joining this ob- 

 servation with the familiar fact that leaves, 

 in common with the larger members of 

 plants, habitually turn themselves to the 

 light, it occurred to me that a natural 

 change in the circumstances of the leaf 

 might readily cause such a modification of 

 form as that which I had produced artifi- 

 cially. If, as they often do with plants, soil 

 and climate were greatly to change the habit 

 of the buttercup, making it branched and 

 shrublike, and if these palmate leaves were 

 thus much overshadowed by one another, 

 would not the inner segments of the leaves 



grow towards the periphery of the plant 

 where the light was greatest, and so change 

 the palmate form into a more decidedly 

 bilateral form? Immediately I began to 

 look round for evidence of the relation be- 

 tween the forms of leaves and the general 

 characters of the plants they belong to, and 

 soon found some signs of connection. Cer- 

 tain anomalies, or seeming anomalies, how- 

 ever, prevented me from then pursuing the 

 inquiry much further. But consideration 

 cleared up these difficulties; and the idea 

 afterwards widened into the general doctrine 

 [of morphological development] here elab- 

 orated. SPENCER Biology, pt. iv, ch. 9, p. 

 160. (A., 1900.) 



3112. 



The Counting of 



Sun-spots Reveals Solar Period. Periodic- 

 ity of the manifestation of solar activity 

 is a fact now proved with the most unques- 

 tionable certainty. It was discovered by 

 him who first thought of counting the spots 

 on the sun. What a beautiful lesson for 

 astronomical amateurs! How discoveries 

 may be thus made by simple curiosity or by 

 perseverance! What could apparently be 

 more childish than the idea of amusing one- 

 self by counting every day the spots on the 

 sun? Nevertheless, the name of Schwabe 

 will remain inscribed in the annals of as- 

 tronomy for having thus discovered this 

 mysterious period of eleven years in the 

 variation of the solar spots. FLAMMARION 

 Popular Astronomy, bk. iii, ch. 5, p. 284. 

 (A.) 



3113. SINGING A PLEASURE TO 

 SONG-BIRDS Brilliancy of Color Does Not 

 Accompany Musical Power. The act of 

 singing is evidently a pleasurable one; and 

 it probably serves as an outlet for super- 

 abundant nervous energy and excitement, 

 just as dancing, singing, and field sports do 

 with us. It is suggestive of this view that 

 the exercise of the vocal power seems to be 

 complementary to the development of acces- 

 sory plumes and ornaments, all our finest 

 singing birds being plainly colored, and with 

 no crests, neck or tail plumes to display, 

 while the gorgeously ornamented birds ^ of 

 the tropics have no song, and those which 

 expend much energy in display of plumage, 

 as the turkey, peacock, birds of paradise, 

 and humming-birds, have comparatively an 

 insignificant development of voice. WAL- 

 LACE Darwinism, ch. 10, p. 192. (Hum.) 



3114. SINGLENESS OF THEORY 

 SOUGHT IN MEDICINE A II Diseases To 

 Be Referred to One Cause" The Four Car- 

 dinal Fluids." What was not right was the 

 [old] delusion that it was more scientific to 

 refer all diseases to one kind of explanation 

 than to several. What was called the " soli- 

 dar pathology " wanted to deduce everything 

 from the altered mechanism of the solid 

 parts, especially from their altered tension; 

 from the strictum and laxum, from tone 

 and want of tone, and afterwards from 



