Influence 

 Inheritance 



SCIENTIFIC SIDE-LIGHTS 



340 



There it is, however, and this minute and 

 seemingly unimportant peculiarity has been 

 found to be full of meaning. PROCTOR 

 Other Worlds than Ours, ch. 2, p. 41. 

 (Burt.) 



1665. INFLUENCE, MYSTERIOUS, 

 OF THE SUN ON THE MAGNETIC NEE- 

 DLE Correspondence of Oscillations of the 

 Needle with Sun-spots. The amplitude of 

 these diurnal oscillations [of the magnetic 

 needle] varies every day, every month, every 

 year. If we take the mean of the observa- 

 tions for a whole year, we ascertain that 

 this oscillation may lengthen from single to 

 double in a period of about 1 1 years, -which 

 period a fact eminently worthy of atten- 

 tion corresponds to that of the solar spots, 

 the mawimum of the oscillations coinciding 

 with the maximum of the spots, and the 

 minimum with the minimum ! All the other 

 elements of magnetism, inclination, and in- 

 tensity show the same relation. Further, 

 the magnetic needle manifests from time to 

 time abnormal variations, perturbations 

 caused by magnetic storms; these pertur- 

 bations also coincide with the great agita- 

 tions observed in the sun! FLAMMARION 

 Popular Astronomy, bk. iii, ch. 5, p. 288. 

 (A.) 



1666. INFLUENCE OF AN EN- 

 LIGHTENED MONARCH Ornithology En- 

 couraged by Queen Isabella. Columbus 

 brought home from his first voyage of dis- 

 covery some natural products, as, for in- 

 stance, fruits and the skins of animals. In 

 a letter written from Segovia (August, 

 1494), Queen Isabella enjoins on the admiral 

 to persevere in his collections ; and she espe- 

 cially requires of him that he should bring 

 with him. specimens of " all the coast and 

 forest birds peculiar to countries which have 

 a different climate and different seasons." 

 HUMBOLDT Cosmos, vol. ii, pt. ii, p. 274. 

 (H., 1897.) 



1667. INFLUENCE OF CULTIVA- 

 TION Evolution of the Cabbage Cause Still 

 To Seek Plants that Stubbornly Resist Im- 

 provement. There is no more remarkable 

 example of the alteration produced by more 

 abundant supply of food and more regulated 

 temperature than that exhibited in the de- 

 velopment of the wild Brassica oleracea, a 

 rambling seashore plant, into the various 

 kinds of cabbage, broccoli, and cauliflower. 

 Why will not culture produce the like effect 

 upon other plants? It is quite illogical to 

 say that this transformation has been the 

 effect of " physical causes," when the most 

 essential factor in that entire " aggregate of 

 antecedents," which (according to J. S. Mill) 

 constitutes the " cause," is the " unknown 

 quantity " which we designate as the " con- 

 stitution " of the organism itself. As I have 

 already pointed out, we do not get any 

 nearer to the explanation of this constitu- 

 tion by tracing it backwards ancestrally; 

 for supposing Rosa, Rubus, Salix, and Bras- 

 sica to have derived their respective pecu- 



liarities by " natural selection " from among 

 previous varieties, the question recurs, 

 Whence those varietal modifications? No 

 physical agencies can be assigned, at any 

 stage whatever of the descent, as an ade- 

 quate account of them ; since, for those agen- 

 cies to take effect there must have been a 

 concurrent capacity for variation, either in 

 the organism itself or in its germ, in virtue 

 of which its varietal forms were engendered. 

 The necessity for this factor is evinced by 

 the negative results of its deficiency, shown 

 in the " rareness " of many wild plants, and 

 the unconquerable resistance made by others 

 to all improvement by cultivation. CARPEN- 

 TER Nature and Man, lect. 15, p. 437. (A., 

 1889.) 



1668. INFLUENCE OF GEOGRAPHIC 

 CONDITIONS ON HISTORY This triple 

 constriction of the Mediterranean [into M- 

 gean, Syrtic, and Tyrrhenian basins] has ex- 

 ercised a great influence on the earliest lim- 

 itations and the subsequent extension of 

 Phenician and Greek voyages of discovery. 

 The latter were long limited to the jEgean 

 and Syrtic seas. In the Homeric times the 

 continent of Italy was still an " unknown 

 land." The Phocseans opened the Tyrrhe- 

 nian basin west of Sicily, and Tartessian 

 mariners reached the Pillars of Hercules. 

 It must not be forgotten that Carthage was 

 founded at the boundary of the Tyrrhenian 

 and Syrtic basins. The physical configura- 

 tion of the coast line influenced the course 

 of events, the direction of nautical under- 

 takings, and the changes in the dominion 

 of the sea; and the latter reacted again on 

 the enlargement of the sphere of ideas. 

 HUMBOLDT Cosmos, vol. ii, pt. ii, p. 120. 

 (H., 1897.) 



1669. INFLUENCE OF HEAT AND 

 COLD ON WATER Ice Lighter than Water. 

 Like almost all other substances, water is 

 expanded by heat and contracted by cold. 

 . . . A small flask is filled with colored 

 water and stopped with a cork. Through 

 the cork passes a glass tube, water-tight, 

 the liquid standing at a certain height in 

 the tube. The flask and its tube resemble the 

 bulb and stem of a thermometer. Applying 

 the heat of a spirit-lamp, the water rises 

 in the tube and finally trickles over the 

 top. Expansion by heat is thus illustrated. 

 Removing the lamp and piling a freezing 

 mixture round the flask the liquid column 

 falls, thus showing the contraction of the 

 water by the cold. But let the freezing mix- 

 ture continue to act, the falling of the col- 

 umn continues to a certain point; it then 

 ceases. The top of the column remains sta- 

 tionary for some seconds, and afterwards 

 begins to rise. The contraction has ceased, 

 and expansion by cold sets in. Let the ex- 

 pansion continue till the liquid trickles a 

 second time over the top of the tube. The 

 freezing mixture has here produced to all 

 appearance the same effect as the flame. 

 In the case of water, contraction by cold 



