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it, or the third behind that ; nor would the crowding of the men close to one 
another make any difference so long as they stood motionless andjrigid like 
statues. Now let these rigid statue-like men be imagined all to become 
giants 150 feet high, which is about the height, perhaps, from the bottom to 
the surface of the glacier there. These taller men would stand just as firmly 
as the shorter did. No pressure downwards would have been created even 
by this addition to the mass. That of every part would be borne in its own 
place, and would not add itself to any other. Now let each of these giants 
become a rectangular column of ice, fitting to the adjacent similar columns, 
and let it be supposed that no column would slip on its base — for we are 
not here concerned with the sliding theory. It would not crush upon its 
base— it must be 700 feet high to do that,|] nor would one cross line of rigid 
columns press downward on the next below, any more than one line of rigid 
men did. Now these columns, thus brought closely in contact, would freeze 
together. Their freezing together (without expansion or contraction) would 
it is true, introduce a new set of forces ; but these forces would be in 
equilibrium with one another, and could not, therefore, interfere with the 
equilibrium of the first set. A glacier would thus be constituted such as 
actually exists, and would not, by its weight, descend. 
But we know, as a matter of fact, that this glacier would descend. There 
must then be some other and greater pressure than that of its weight 
acting upon it in the direction of its descent. This conclusion depends, you 
will see, upon the fact proved by experiment, that it requires a height of 700 
feet of ice and upwards to cause ice to crush itself, and that the columns of 
ice of which the glacier is imagined to be composed are rigid, so that the 
glacier would not bulge out at its sides by its own weight, as a mass of 
mud would, or soft plaster, or soft pitch, or putty ; for we see, in point of 
fact, that glaciers do not so bulge out when their sides are laid bare. 
There is another way of looking at the question, which leads to the same 
conclusion. If, instead of ice, the glacier were water it would descend by 
its weight. The same would be true if it were of oil or soft mud, or probably 
of pitch or quicksilver; but if it were of iron, or of copper, or of lead, it would 
not descend by its weight only, unless, indeed, these metals were in a state 
of fusion. There must, therefore, be some substance between the consistency 
of iron aud quicksilver, which would just, of which if the glacier were composed 
it would only just, descend by its weight. The difference between the sub- 
stances, say, iron and quicksilver, (so far as this result is concerned) is that the 
|| The crushing force of ice measured, in the case of a solid cylinder 1£ 
inches in diameter and G inches long, was found to be at the rate of 120 
lbs. per square inch. 
