Division 

 Doing 



SCIENTIFIC SIDE-LIGHTS 



182 



the transmission. In the case of the as- 

 bestos, the fibers are separated from each 

 other by spaces of air; the motion has to 

 pass from solid to air, and from air to solid. 

 It is easy to see that the transmission of 

 vibratory motion through this composite 

 texture must be very imperfect. In the case 

 of an animal's fur this is more especially 

 the case ; for here, not only do spaces of air 

 intervene between the hairs, but the hairs 

 themselves, unlike the fibers of the asbestos, 

 are very bad conductors. Lava has been 

 known to flow over a layer of ashes under- 

 neath which was a bed of ice, the non-con- 

 ductivity of the ashes saving the ice from 

 fusion. Red-hot cannon-balls have been 

 wheeled to the gun's mouth in wooden bar- 

 rows partially filled with sand. Ice is 

 packed in sawdust, to prevent it from melt- 

 ing; powdered charcoal is also an eminent- 

 ly bad conductor. TYNDAIX Heat a Mode of 

 Motion, lect. 9, p. 258. (A., 1900.) 



889. DIVISION OF BIELA'S COMET 



An Unexpected Astronomical Spectacle. 

 It [Biela's comet] was seen again in 1845, 

 on November 25, near the place assigned to 

 it by calculation, and its course was duly 

 followed. Everything went on to the gen- 

 eral satisfaction, when unexpected spec- 

 tacle! on January 13, 1846, the comet split 

 into two! What had passed in its bosom? 

 Why this separation? What was the cause 

 of such a celestial cataclysm? We do not 

 know; but the fact is that, instead of one 

 comet, two were henceforth seen, which con- 

 tinued to move in space like two twin sisters 

 two veritable comets, each having its 

 nucleus, its head,, its coma, and its tail, 

 slowly separating from each other ; on Feb- 

 ruary 10 there was already 60,000 leagues 

 (about 149,000 miles) of space between the 

 two. They would seem, however, to have 

 parted with regret, and during several days 

 a sort of bridge was seen thrown from one 

 to the other. The cometary couple, depart- 

 ing from the earth, soon disappeared in the 

 infinite night. 



They returned within view of the earth in 

 the month of September, 1852; on the 26th 

 of this month the twins reappeared, but 

 much farther apart, separated by an inter- 

 val of 500,000 leagues (about 1,250,000 

 miles). FLAMMARION Popular Astronomy, 

 bk. v, ch. 2, p. 499. (A.) 



89O. DIVISION OF LABOR Among 

 Ancient Organisms Distinctive Organs Mark 

 Higher Type of Structure. Other species of 

 bivalves were also introduced, approaching 

 more nearly our clams and oysters. . . . 

 They differ from the brachiopods chiefly in 

 the higher character of their breathing ap- 

 paratus; for they have free gills, instead of 

 the network of vessels -on the lining skin 

 which serves as the organ of respiration in 

 the brachiopods. We shall always find that 

 in proportion as the functions are distinct, 

 and, as it were, individualized by having 

 special organs appropriated to them, ani- 



mals rise in the scale of structure. 

 AGASSIZ Geological Sketches, ser. i, ch. 3, p. 

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



891. 



Between Associated 



Organisms Lichens Communities of Algce 

 and Fungi Organisms Mutually Coopera- 

 ting. Incredible as the statement once 

 seemed, it is a statement now accepted, that 

 what we know as lichens, and used to con- 

 sider as plants forming a certain low class, 

 are now found to be not plants in the ordi- 

 nary sense at all, but compound growths 

 formed of minute algae and minute fungi, 

 carrying on their lives together: the algae 

 furnishing to the fungi certain constituents 

 they need, but cannot directly obtain, and 

 the fungi profiting by certain materials they 

 obtain from the alga?, either while living 

 or while individually decaying. Whence it 

 would seem that after the microscopic vege- 

 tal type had become in a large degree dif- 

 ferentiated into two main types, in adapta- 

 tion to different conditions of life, and had 

 acquired appropriate specialties of nature, 

 there grew up this communistic arrange- 

 ment between certain of them, enabling each 

 to benefit by the powers which the other had 

 acquired : evidently an exchange of services, 

 a physiological division of labor, a mutual 

 dependence of functions analogous to that 

 which exists between functions in an ordi- 

 nary plant or animal. SPENCER Biology, pt. 

 v, ch. 10A, p . 339. (A., 1900.) 



892. Marks the Progress 



of Nations. A comparative survey of the 

 history of nations, or what is called " uni- 

 versal history," will readily yield to us, as 

 the first and most general result, evidence of 

 a continually increasing variety of human 

 activities, both in the life of individuals and 

 in that of families and states. This differ- 

 entiation or separation, this constantly in- 

 creasing divergence of human character and 

 the form of human life, is caused by the 

 ever advancing and more complete division 

 of labor among individuals. While the most 

 ancient and lowest stages of human civili- 

 zation show us throughout the same rude 

 and simple conditions, we see in every suc- 

 ceeding period of history, among different 

 nations, a greater variety of customs, prac- 

 tises, and institutions. HAECKEL History of 

 Creation, vol. i, ch. 12, p. 319. (K. P. & Co., 

 1899.) 



893. DIVISION OF PERSONALITY 

 BY PHRENOLOGY .Horse Inside of Loco- 

 motive. " We have [according to phrenol- 

 ogy] a parliament of little men together, 

 each one of whom, as happens also in a real 

 parliament, possesses but a single idea which 

 he ceaselessly strives to make prevail " 

 benevolence, firmness, hope, and the rest. 

 " Instead of one soul, phrenology gives us 

 forty, each alone as enigmatic as the full ag- 

 gregate psychic life can be. Instead of divi- 

 ding the latter into effective elements, she 

 divides it into personal beings of peculiar 

 character. . . . ' Herr Pastor, sure there 



