167 



SCIENTIFIC SIDE-LIGHTS 



Development 

 Dew 



ing and sharpening his claws. Natural se- 

 lection is the keenest capitalist in the uni- 

 verse; she never loses an instant in seizing 

 the most profitable place for investment, and 

 her judgment is never at fault. FISKE 

 Through Nature to God, pt. ii, ch. 5, p. 83. 

 (H. M. & Co., 1900.) 



815. DEVIATIONS INHERITABLE 



The number and diversity of inheritable de- 

 viations of structure, both those of slight 

 and those of considerable physiological im- 

 portance, are endless. Dr. Prosper Lucas's 

 treatise, in two large volumes, is the fullest 

 and the best on this subject. No breeder 

 doubts how strong is the tendency to in- 

 heritance; that like produces like is his 

 fundamental belief: doubts have been 

 thrown on this principle only by theoretical 

 writers. [See HEREDITY OF ACQUIRED CHAR- 

 ACTERS.] DARWIN Origin of Species, ch. 1, 

 p. 12. (Burt.) 



816. DEVICE COMMON TO DIVERSE 

 PEOPLES Falcons of the Sea^A Sucking- 

 fish as Captor of Other Fishes. In the time 

 of Columbus the now desolate district of the 

 Jardines del Rey was animated by a singu- 

 lar branch of industry pursued by the in- 

 habitants of the seacoasts of Cuba, who 

 availed themselves of a little fish, the re- 

 mora, or sucking-fish (the so-called ship- 

 holder), probably the Echeneis naucrates, 

 for catching turtles. A long and strong line, 

 made of the fibers of the palm, was attached 

 to the tail of the fish. The remora (called 

 in Spanish reves, or reversed, because at first 

 sight the back and abdomen might easily be 

 mistaken for each other) attaches itself by 

 suction to the turtle through the indented 

 and movable cartilaginous plates of the 

 upper shell that covers the head. The re- 

 mora, says Columbus, would rather let itself 

 be torn to pieces than relinquish its prey, 

 and the little fish and the turtle are thus 

 drawn out of the water together. . . . 

 We learn from Dampier and Commerson 

 that this artifice of employing a sucking- 

 fish to catch other fishes is very common on 

 the eastern coasts of Africa, near Cape 

 Natal and Mozambique, as well as on the 

 island of Madagascar. An acquaintance 

 with the habits of animals, and the same 

 necessities, lead to similar artifices and 

 modes of capture amongst tribes having no 

 connection with one another. HUMBOLDT 

 Views of Nature, p. 257. (Bell, 1896.) 



817. DEVICES FOR EXPLAINING 

 THE MYSTERY OF EVIL Comte Would 

 Have Improved the Tilt of the Earth's Axis. 

 [To explain the mystery of evil] it has 

 usually been found necessary to represent 

 the Creator as finite either in power or in 

 goodness, altho the limitation is seldom 

 avowed, except by writers who have a lean- 

 ing toward atheism and take a grim pleas- 

 ure in pointing out flaws in the constitution 

 of things. Among modern writers the most 



conspicuous instance of this temper is af- 

 forded by that much too positive philoso- 

 pher, Auguste Comte, who would fain have 

 tipped the earth's axis at a different angle 

 and altered the arrangements of Nature in 

 many fanciful ways. He was like Alphonso, 

 the learned king of Castile, who regretted 

 that he had not been present when the world 

 was created he could have given such ex- 

 cellent advice! FISKE Through Nature to 

 God, pt. i, ch. 3, p. 12. (H. M. & Co., 1900.) 



818. DEVOTION TO SCIENCE Von 



Buch Traverses Europe on Foot for Ge- 

 ologic Study Unites the Aqueous and 

 Igneous Theories. It was a pupil of Wer- 

 ner's who at last set at rest this much-vexed 

 question [between the aqueous and the 

 igneous origin of rocks]. 



At the age of sixteen, in the year 1790, 

 Leopold von Buch was placed under Wer- 

 ner's care at the mining school of Freiberg. 

 . . . Von Buch was indefatigable. For 

 years he lived the life of an itinerant ge- 

 ologist. With a shirt and a pair of stock- 

 ings in his pocket, and a geological hammer 

 in his hand, he traveled all over Europe on 

 foot. The results of his foot-journey to 

 Scandinavia were among his most important 

 contributions to geology. He went also to 

 the Canary Islands; and it is in his exten- 

 sive work on the geological formations of 

 these islands that he showed conclusively 

 not only the Plutonic character of all un- 

 stratified rocks, but also that to their action 

 upon the stratified deposits the inequalities 

 of the earth's surface are chiefly due. He 

 first demonstrated that the melted masses 

 within the earth had upheaved the materials 

 deposited in layers upon its surface, and had 

 thus formed the mountains. AGASSIZ Ge- 

 ological Sketches, ser. i, ch. 4, p. 111. 

 (H. M. &Co., 1896.) 



819. DEW, FORMATION OF Nice 

 Balance of Atmospheric Moisture and Tem- 

 perature Provided for. Dew forms more 

 readily and more abundantly on grass, on 

 account of the numerous centers of conden- 

 sation it affords. Dew, however, is now 

 formed only on clear cold nights after warm 

 or moist days. The air near the surface is 

 warm and contains much vapor, tho below 

 the point of saturation. But the innumer- 

 able points and extensive surfaces of grass 

 radiate heat quickly, and becoming cool, 

 lower the temperature of the adjacent air, 

 which then reaches saturation-point and 

 condenses the contained vapor on the grass. 

 Hence, if the atmosphere at the earth's sur- 

 face became supersaturated with aqueous 

 vapor, dew would be continuously deposited, 

 especially on every form of vegetation, the 

 result being that everything, including our 

 clothing, would be constantly dripping wet. 

 If there were absolutely no particles of solid 

 matter in the upper atmosphere, all the 

 moisture would be returned to the earth in 

 the form of dense mists, and frequent and 



