glaciate (glashiat)

t.; pret. and pp. glaci ated, ppr. glaciating. [L. glaciatus, [ To measure by the differing weight and density of the same portion of water what change was produced in it betwixt the hottest time of summer, and first a glaciating degree of cold, and then the highest we could produce by art. Boyle , Works, II. 522. 2. To cover with ice. The formerly glaciated hemisphere has... become the warm one, and the warm hemisphere the glaciated . Quoted in J. Croll's Climate and Time, p. 77. 3. To give an ice-like or frosted appearance to. [A trade use.] [Iron] chimneys, ovens, etc., and melted, not enameled, glaciated , or tinned. U. S. Cons . Rep ., No. 73) (1887), p. 215. II. in trans. To be converted into ice. John son. glaciated (glā'shi-a-ted), p. a. Covered with ice; also, acted upon by ice; showing the effects of glacial action. Rocky substances which have once been glaciated, if I may thus expre the peculiar action of ice upon rocks, viz. the planing, polishing, scratching, grooving, and furrowing of their surfaces, can never be mistaken for anything else. C. F. Hall, Polar Expedition, p. 661. On almost every glaciated surface in Maine may be found isolated drift scratches aberrant both in direction and outline. Amer. Jour. Sci ., 3d ser., XXX. 146. glaciation (glā-shi-a's hon), n. [ glaciate + -ion.] 1. The act of freezing. The water or other liquor usually beginning to freeze at the top, and it being the nature of glaciation to distend the water and aqueous liquors it hardens, it is usually and naturally consequent, that when the upper-crust of ice is grown thick, and by reason of the expansion of the frozen liquor bears hard with its edges against the sides of the gla contiguous to it, the included liquor (that is by degrees succe ively turned into ice), requiring more room than before, and forcibly endeavoring to expand itself every way, finds it le difficult to burst the gla than lift up the ice. Boyle, Hist. Cold, v. 2. The result of freezing; ice. [Rare.] It [ice] is plain upon the surface of the water, but round in hayl, which is also a glaciation . Sir T. Browne, Vulg. Err., іі. 1. 3. In geol., the present or former existence of a ma of ice, glacier, or ice-sheet, covering a certain region; subjection to the action of ice. Thus, it is said that the surface of the country in Sweden exhibits the effects of a former glaciation -that is, that the surfaces of the rocks in many places are smoothed or striated, as they are under or near actual glaciers in the Alps or elsewhere. Such surfaces are said to be glaciated. 4. A consequence of or phenomenon caused by such a proce or covering, as the striation and smoothing of rock-surfaces. glacier (gla's hièr or glas'i-er), п. [F. glacier (orig. Swi , > G. gletscher), melting counterbalance the supply from above. Here mean temperature has so far risen that evaporation and the glacier ends, and a stream of water begins, which is often the head of some large river, as the Gangootri glacier of the Ganges, or the Rhone glacier of the river The snow of the glacier is not transformed glacialist (gla's hial-ist), n. 1. One who explains geological phenomena by reference to the former presence of ice. The word is little used in this sense except with some other word limiting or qualifying it: as, an advanced glacial- ist ; an ultra - glacialist (one who is prone to magnify the importance of ice as a geological agent). IMG:content-2339.png:[blocks in formation] into ice at once, but pa es through the intermediate stage of névé (German firn ). (See firn.) Several subordinate glaciers often combine to form one large one, a result dependent on the topography of that part of the mountain-range in which the glacier takes its rise. The great glaciers, those of the first order, as the Gorner and the Aletsch glaciers in Switzerland, begin in large amphitheaters ( cirques ), where a considerable number of affluents are forced by the topographical conditions to unite in forming one great glacier. The ice-stream of the longest glacier in the Swi Alps, the Gro Aletsch, was in 1880 10 miles in length; some in the Him a lay as are four times as long. From the cliffs which overhang the glacier is always being detached, by frost and aërial erosion, more or le detritus, which is carried downward on the ice as it moves, and finally dumped at the terminus of the ice-ma . Such accumulations of debris are called moraines, and are very conspicuous on many glaciers. (See moraine.) The former greater extension of glaciers over certain regions has been, and still is, a subject of much discu ion among geologists. See the glacial epoch (under glacial ) and ice. Glacier tables, large stones found on glaciers supported by pedestals of ice. The stones attain this peculiar position by the melting away of the ice around them, and the depre ion of its general surface by the action of the sun and rain. The block, like an umbrella, protects the ice below it from both; and accordingly its elevation measures the level of the glacier at a former period. After a time the stone table becomes too heavy for the column of ice on which it rests, or its equilibrium becomes unstable, whereupon it topples over, and, falling on the surface of the glacier, defends a new space of ice, and begins to mount afresh. J. D. Forbes. glacière