584 GEOLOGY OF MOUNTAINS. 



or a passion for dangerous enterprise such as stimulates the pioneer 

 or the explorer, or a powerful scientific and artistic interest, can 

 impel the Alpine adventurer can instigate a Saussure, a Forbes, a 

 Pentland, or a Tyndall, to mount the scarped ramparts of primeval 

 rocks, to tread warily along precipices which the chamois can scarcely 

 traverse, to escalade the savage cliffs and frozen pinnacles, and to 



breathe 



" The difficult air of the iced mountain-tops." 



The annals of mountaineering are illuminated with many stirring 

 stories of human endurance, patience, and heroism ; but, alas ! the 

 page is too often robed in black, and too frequently records the death 

 of some unhappy explorer 



It is no part of my plan to trace the geological history of moun- 

 tains. We know that their formation has been attributed, according 

 to a satisfactory theory, to the upheavals and expansions of the 

 igneous matter which, in the primitive ages, boiled under the solid 

 crust produced by the superficial solidification of our planet, and 

 whose ebullition, though considerably decreased, even in our own 

 days is frequently made known in volcanic phenomena and earth- 

 quakes. At divers epochs the crust of the globe will have been rent 

 and dislocated, giving vent to floods of fused mineral matter ; these, 

 solidifying in their tunn, will have produced those inequalities of the 

 earth's surface which we call mountains; enormous inequalities, as 

 they appear to us ; mole-hills or grains of sand if we compare them 

 with the volume of the terresti'ial sphere. 



The distribution of the mountains over the surface of the con- 

 tinents and islands, and the forms which they have assumed, seem, 

 at the first glance, altogether capricious and irregular. Yet an 

 attentive study speedily demonstrates that some higher law than that 

 of chance presided at the violent and tumultuous production of these 

 majestic masses. Thus, in the first place, it is evident that every 

 mountain not a volcano connects itself of necessity to other moun- 

 tains, and forms a chain of greater or less length, which departs a 

 little from the straight line, or rather from the arc of the great circle. 



