284 MOUNTAIN SLIDES. 
the mountains is due to the destruction of the forests—that the 
flanks of every Alpine valley in Central Europe below the 
snow-line were once covered with earth and green with woods, 
but there are not many particular cases in which we can, with 
certainty, or even with strong probability, affirm the contrary. 
Mountain Slides. 
Terrible as are the ravages of the torrent and the river-flood, 
the destruction of the woods exposes human life and industry 
to calamities even more appalling than those which I have yet 
described. The slide in the Notch of the White Mountains, by 
which the Willey family lost their lives, is an instance of the 
sort I refer to, though I am not able to say that in this particu- 
lar case the slip of the earth and rock was produced by the 
denudation of the surface. It may have been occasioned by 
this cause, or by the construction of the road through the Notch, 
the excavations for which, perhaps, cut through the natural 
buttresses that supported the sloping strata above. 
Not to speak of the fall of earth when the roots which held 
it together, and the bed of leaves and mould which sheltered 
In all the great operations of terrestrial nature, the elements are so numerous 
and so difficult of exact appreciation, that, until the means of scientific obser- 
vation and measurement are much more perfected than they now are, we 
must content ourselves with general approximations. I say terrestrial nature, 
because in cosmical movements we have fewer elements to deal with, and may 
therefore arrive at much more rigorous proportional accuracy in determination 
of time and place than we can in fixing and predicting the quantities and the 
epochs of variable natural phenomena on the earth’s surface. 
Travellers are often misled by local habits in the use of what may be called 
representative numbers, where a definite is put for an indefinite quantity. <A 
Greek, who wished to express the notion of a great but undetermined num- 
ber, used ‘‘myriad, or ten thousand; ” a Roman, ‘‘ six hundred ;” an Orien- 
tal, ‘‘ forty,” or, at present, very commonly, ‘‘fifteen thousand.” Many a 
tourist has gravely repeated, as an ascertained fact; the vague statement of 
the Arabs and the monks of Mount Sinai, that the ascent from the convent 
of St. Catherine to the summit of Gebel Moosa counts ‘* fifteen thousand ” 
steps, though the difference of level is two thousand feet; and the ‘‘ Forty” 
Thieves, the ‘‘ forty” martyr-monks of the convent of El Arbain—not to 
