ce 



ce-clouds 



SCIENTIFIC SIDE-LIGHTS 



314 



depth may be fully equal to the height of 

 the surface above the sea, or about 8,000 

 feet. RUSSELL Glaciers of North America, 

 ch. 7, p. 133. (G. & Co., 1897.) 



1530. ICE, CONTINUED ACTIVITY OF 



At the first freezing, water, like any other 

 substance, shrinks, but with increasing cold 

 it expands, and in fact to such an extent 

 that it breaks every limiting barrier, a pro- 

 ceeding during which it actually becomes 

 lighter, consequently it must be constantly 

 changing its inner structure, must be con- 

 stantly developing. It is by means of this 

 activity of ice that it gradually works to 

 the surface the immense granite blocks 

 which sink deep under the ice high up on 

 the glacier. Glacial ice never contains en- 

 closed fragments of rock. BUCHHEISTER 

 Eine wissenschaftliche Alpenreise im Win- 

 ter, 1832, p. 16. (Translated for Scientific 

 Side-Lights.) 



1531. ICE EXPANDS BY MEANS OF 

 AIR-BUBBLES Glacier-ice is everywhere 

 found honeycombed by a system of air-bub- 

 bles. Every icy surface that forms over 

 quiet water contains a countless number of 

 air-holes in very regular layers, of which 

 the upper are all thin and pointed, like 

 a bodkin, all of whose outermost sharp points 

 turn toward the atmosphere. All of the 

 fundamental strata of river-ice contain a 

 complication of bubbles and nets of bubbles, 

 that remind one of cell-tissues. The active 

 development of these bubbles increases with 

 the degree of cold and the formation of 

 ice, and is the obvious reason why ice ex- 

 pands. BUCHHEISTER Eine wissenschaft- 

 liche Alpenreise im Winter, 1832. (Trans- 

 lated for Scientific Side-Lights.) 



1532. ICE, FAIRY-LAND OF Beauty 

 of Alaskan Glaciers Rich and Varied Col- 

 ors The Blue of the Crystal Mass. The 

 color of the fractured and cleft ice-cliffs 

 [of Taku glaciers] is as varied and beau- 

 tiful as their ever-changing forms. The sur- 

 faces that have been longest exposed to the 

 atmosphere are white and glittering, on ac- 

 count of the multitude of vesicles formed in 

 the partially melted ice; but the clefts and 

 caverns reveal the intense blue of the crys- 

 tal mass within. In the deeper recesses the 

 light issuing from the interior is of the 

 darkest ultramarine, so deep that it ap- 

 pears almost black in contrast with the bril- 

 liant outer surface. In the full glory of an 

 unclouded summer day the scene becomes re- 

 splendent with the reflected glories of the 

 sea and sky. The ice-cliffs blaze and flash in 

 the sunlight until one can scarcely believe 

 that it is an every-day, earthly scene that 

 meets his admiring gaze. The observer to 

 whom such wonders are novel may well fan- 

 cy that the picture before him is but the 

 fantasy of a dream. One is awakened from 

 such reverie, however, by a crash like the 

 roar of artillery, when an avalanche falls 

 from the cliffs of light and is engulfed in 

 the turbid waters below. The white foam 



shot upwards by the avalanche rises high 

 on the icy precipice, and perhaps dislodges 

 other tottering pinnacles, which reawaken 

 the echoes in the neighboring mountains. 

 After each crash, crested waves, starting 

 away from the scene of commotion, set nu- 

 merous bergs rocking, and break in lines of 

 foam on the adjacent shore. RUSSELL Gla- 

 ciers of North America, ch. 6, p. 79. (G. 

 & Co., 1897.) 



1533. ICE REMOLDED BY BREAKING 

 AND FREEZING Fracture and Regelation. 

 [Investigation] suggested the thought that 

 if a piece of ice a straight prism, for ex- 

 ample were placed in a bent mold and sub- 

 jected to pressure it would break, but that 

 the force would also bring its ruptured sur- 

 faces into contact, and thus the continuity 

 of the mass might be reestablished. Ex- 

 periment . . . completely confirmed this 

 surmise; the ice passed from a continuous 

 straight bar to a continuous bent one, the 

 transition being effected, not by a viscous 

 movement of the particles, but through frac- 

 ture and regelation. 



Let the transition from curve to curve 

 be only gradual enough, and we have the 

 exact case of a transverse slice of a glacier. 

 TYNDALL Hours of Exercise in the Alps, 

 ch. 1, p. 354. (A., 1898.) 



1534. ICE SUPPOSED TO BE FORMED 

 BY HEAT Physical Conceptions of the An- 

 cients Supposed Law of Contraries. The 

 ideas that fire has the power of making 

 rigid, . . . and that the formation of 

 ice itself may be promoted by heat, are 

 deeply rooted in the physics of the ancients 

 and based on a fanciful theory of contraries 

 (Antiperistasis) on obscure conceptions of 

 polarity (of exciting opposite qualities or 

 conditions). . . . The quantity of hail 

 produced was considered to be proportional 

 to the degree of heat of the atmospheric 

 strata. In the \vinter fishery on the shores 

 of the Euxine, warm water was used to in- 

 crease the ice formed in the neighborhood of 

 an upright tube. HUMBOLDT Cosmos, vol. 

 iii, p. 125. (H., 1897.) 



1535. ICE, TRANSPORTING POWER 



OF Rocks Borne Along Like Chips. In Can- 

 ada, where the winter's cold is intense, 

 in a latitude corresponding to that of central 

 France, several tributaries of the St. Law- 

 rence begin to thaw in their upper course, 

 while they remain frozen over lower down, 

 and thus large slabs of ice are set free and 

 thrown upon the unbroken sheet of ice be- 

 low. Then begins what is called the packing 

 of the drifted fragments; that is to say, one 

 slab is made to slide over another, until a 

 vast pile is built up, and the whole, being 

 frozen together, is urged onwards by the 

 force of the dammed-up waters and drift- 

 ice. Thus propelled, it not only forces along 

 boulders, but breaks off from cliffs, which 

 border the rivers, huge pieces of projecting 

 rock. By this means several buttresses of 

 solid masonry, which up to the year 1836 



