have refreshment in a little mountain hut. We then pass the _Mauvais
Pas_, a precipitous rock, on the face of which steps are hewn, and
the unpractised traveller is assisted by a rope. We pursue our
journey, partly along the mountain side, and partly along a ridge of
singularly artificial aspect a _lateral moraine_. We at length face a
house perched upon an eminence at the opposite side of the glacier.
This is the auberge of the Montanvert, well known to all visitors to
this portion of the Alps.
110. Here we cross the glacier. I should have told you that its lower
part, including the broken portion we have passed, is called the
Glacier des Bois; while the place that we are now about to cross is
the beginning of the Mer de Glace. You feel that this term is not
quite appropriate, for the glacier here is much more like a _river_
of ice than a sea. The valley which it fills is about half a mile
wide.
111. The ice may be riven where we enter upon it, but with the
necessary care there is no difficulty in crossing this portion
of the Mer de Glace. The clefts and chasms in the ice are called
_crevasses_; we shall make their acquaintance on a grander scale by
and by.
[Illustration: THE MER DE GLACE, SHOWING MONT TACUL AND THE GRANDE
JORASSE, WITH OUR CLEFT ABOVE TRÉLEPORTE TO THE RIGHT.]
112. Look up and down this side of the glacier. It is considerably
riven, but as we advance the crevasses will diminish, and we shall
find very few of them at the other side. Note this for future use.
The ice is at first dirty; but the dirt soon disappears, and you come
upon the clean crisp surface of the glacier. You have already noticed
that the clean ice is white, and that from a distance it resembles
snow rather than ice. This is caused by the breaking up of the
surface by the solar heat. When you pound transparent rock-salt into
powder it is as white as table-salt, and it is the minute fissuring
of the surface of the glacier by the sun's rays that causes it to
appear white. _Within_ the glacier the ice is transparent. After an
exhilarating passage we get upon the opposite lateral moraine, and
ascend the steep slope from it to the Montanvert Inn.
§ 13. _The Mer de Glace and its Sources. Our First Climb to the Cleft
Station._
113. Here the view before us is very grand. We look across the
glacier at the beautiful pyramid of the Aiguille du Dru (shown in our
frontispiece); and to the right at the Aiguille des Charmoz, with
its sharp pinnacles bent as if they were ductile. Looking straight
up the glacier the view is bounded by the great crests called La
Grande Jorasse, nearly 14,000 feet high. Our object now is to get
into the very heart of the mountains, and to pursue to its origin the
wonderful frozen river which we have just crossed.
114. Starting from the Montanvert with, the glacier below us to our
left, we soon reach some rocks resembling the Mauvais Pas; they are
called _les Fonts_. We cross them and reach _l'Angle_, where we quit
the land for the ice. We walk up the glacier, but before reaching
the promontory called Trélaporte, we take once more to the mountain
side; for though the path here has been forsaken on account of its
danger, for the sake of knowledge we are prepared to incur danger
to a reasonable extent. A little glacier reposes on the slope to
our right. We may see a huge boulder or two poised on the end of
the glacier, and, if fortunate, also see the boulder liberated and
plunging violently down the slope. Presence of mind is all that is
necessary to render our safety certain; but travellers do not always
show presence of mind, and hence the path which formerly led over
this slope has been forsaken. The whole slope is cumbered by masses
of rock which this little glacier has sent down. These I wished you
to see; by and by they shall be fully accounted for.
115. Above Trélaporte to the right you see a most singular cleft in
the rocks, in the middle of which stands an isolated pillar, hewn out
by the weather. Our next object is to get to the tower of rock to
the left of that cleft, for from that position we shall gain a most
commanding and instructive view of the Mer de Glace and its sources.
116. The cleft referred to, with its pillar, may be seen to the
right of the preceding engraving of the Mer de Glace. Below the cleft
is also seen the little glacier just referred to.
117. We may reach this cleft by a steep gully, visible from our
present position, and leading directly up to the cleft. But these
gullies, or couloirs, are very dangerous, being the pathways of
stones falling from the heights. We will therefore take the rocks
to the left of the gully, by close inspection ascertain their
assailable points, and there attack them. In the Alps as elsewhere
wonderful things may be done by looking steadfastly at difficulties,
and testing them wherever they appear assailable. We thus reach our
station, where the glory of the prospect, and the insight that we
gain as to the formation of the Mer de Glace, far more than repay us
for the labour of our ascent.
118. For we see the glacier below us, stretching its frozen tongue
downwards past the Montanvert. And we now find this single glacier
branching out into three others, some of them wider than itself.
Regard the branch to the right, the Glacier du Géant. It stretches
smoothly up for a long distance, then becomes disturbed, and then
changes to a great frozen cascade, down which the ice appears to
tumble in wild confusion. Above the cascade you see an expanse of
shining snow, occupying an area of some square miles.
§ 14. _Ice-cascade and Snows of the Col du Géant._
119. Instead of climbing to the height where we now stand, we might
have continued our walk upon the Mer de Glace, turned round the
promontory of Trélaporte, and walked right up the Glacier du Géant.
We should have found ice under our feet up to the bottom of the
cascade. It is not so compact as the ice lower down, but you would
not think of refusing to call it ice.
120. As we approach the fall, the smooth and unbroken character of
the glacier changes more and more. We encounter transverse ridges
succeeding each other with augmenting steepness. The ice becomes more
and more fissured and confused. We wind through tortuous ravines,
climb huge ice-mounds, and creep cautiously along crumbling crests,
with crevasses right and left. The confusion increases until further
advance along the centre of the glacier is impossible.
121. But with the aid of an axe to cut steps in the steeper ice-walls
and slopes we might, by swerving to either side of the glacier, work
our way to the top of the cascade. If we ascended to the right,
we should have to take care of the ice avalanches which sometimes
thunder down the slopes; if to the left, we should have to take care
of the stones let loose from the Aiguille Noire. After we had cleared
the cascade, we should have to beware for a time of the crevasses,
which for some distance above the fall yawn terribly. But by caution
we could get round them, and sometimes cross them by bridges of snow.
Here the skill and knowledge to be acquired only by long practice
come into play; and here also the use of the Alpine rope suggests
itself. For not only are the 'snow bridges often frail, but whole
crevasses are sometimes covered, the unhappy traveller being first
made aware of their existence by the snow breaking under his feet.
Many lives have thus been lost, and some quite recently.
122. Once upon the plateau above the ice-fall we find the surface
totally changed. Below the fall we walked upon ice; here we are
upon snow. After a gentle but long ascent we reach a depression of
the ridge which bounds the snow-field at the top, and now look over
Italy. We stand upon the famous Col du Géant.
123. They were no idle scamperers on the mountains that made these
wild recesses first known; it was not the desire for health which
now brings some, or the desire for grandeur and beauty which brings
others, or the wish to be able to say that they have climbed a
mountain or crossed a col, which I fear brings a good many more; it
was a desire for _knowledge_ that brought the first explorers here,
and on this col the celebrated De Saussure lived for seventeen days,
making scientific observations.
§ 15. _Questioning the Glaciers._
124. I would now ask you to consider for a moment the facts which
such an excursion places in our possession. The snow through which
we have in idea trudged is the snow of last winter and spring. Had
we placed last August a proper mark upon the surface of the snow, we
should find it this August at a certain depth beneath the surface. A
good deal has been melted by the summer sun, but a good deal of it
remains, and it will continue until the snows of the coming winter
fall and cover it. This again will be in part preserved till next
August, a good deal of it remaining until it is covered by the snow
of the subsequent winter. We thus arrive at the certain conclusion
that on the plateau of the Col du Géant _the quantity of snow that
falls annually exceeds the quantity melted_.
125. Had we come in the month of April or May, we should have found
the glacier below the ice-fall also covered with snow, which is now
entirely cleared away by the heat of summer. Nay, more, the ice there
is obviously melting, forming running brooks which cut channels in
the ice, and expand here and there into small blue-green lakes. Hence
you conclude with certainty that below the ice-fall _the quantity of
frozen material falling upon the glacier is less than the quantity
melted_.
126. And this forces upon us another conclusion: between the glacier
below the ice-fall and the plateau above it there must exist a line
where the quantity of snow which falls _is exactly equal_ to the
quantity annually melted. This is the _snow-line_. On some glaciers
it is quite distinct, and it would be distinct here were the ice less
broken and confused than it actually is.
127. The French term _névé_ is applied to the glacial region above
the snow-line, while the word _glacier_ is restricted to the ice
below it. Thus the snows of the Col du Géant constitute the névé of
the Glacier du Géant, and in part, the névé of the Mer de Glace.
128. But if every year thus leaves a residue of snow upon the plateau
of the Col du Géant, it necessarily follows that the plateau must get
annually higher, _provided the snow remain upon it_. Equally certain
is the conclusion that the whole length of the glacier below the
cascade must sink gradually lower, _if the waste of annual melting
be not made good_. Supposing two feet of snow a year to remain upon
the Col, this would raise it to a height far surpassing that of Mont
Blanc in five thousand years. Such accumulation must take place if
the snow remain upon the Col; but the accumulation does _not_ take
place, hence the snow does not remain on the Col. The question then
is, whither does it go?
[Illustration: SKETCH-PLAN, SHOWING THE MORAINES, _a_, _b_, _c_, _d_,
_e_, OF THE MER DE GLACE.]
§ 16. _Branches and Medial Moraines of the Mer de Glace from the
Cleft Station._
129. We shall grapple with this question immediately. Meanwhile
look at that ice-valley in front of us, stretching up between Mont
Tacul and the Aiguille de Léchaud, to the base of the great ridge
called the Grande Jorasse. This is called the Glacier de Léchaud. It
receives at its head the snows of the Jorasse and of Mont Mallet,
and joins the Glacier du Géant at the promontory of the Tacul. The
glaciers seem welded together where they join, but they continue
distinct. Between them you clearly trace a stripe of débris (_c_ on
the annexed sketch-plan); you trace a similar though smaller stripe
(_a_ on the sketch), from the junction of the Glacier du Géant with
the Glacier des Périades at the foot of the Aiguille Noire, which you
also follow along the Mer de Glace.
130. We also see another glacier, or a portion of it, to the left,
falling apparently in broken fragments through a narrow gorge
(Cascade du Talèfre on the sketch) and joining the Léchaud, and from
their point of junction also a stripe of débris (_d_) runs downwards
along the Mer de Glace. Beyond this again we notice another stripe
(_e_), which seems to begin at the bottom of the ice-fall, rising
as it were from the body of the glacier. Beyond all of these we can
notice the lateral moraine of the Mer de Glace.
131. These stripes are the _medial moraines_ of the Mer de Glace. We
shall learn more about them immediately.
132. And now, having informed our minds by these observations, let
our eyes wander over the whole glorious scene, the splintered peaks
and the hacked and jagged crests, the far-stretching snow-fields, the
smaller glaciers which nestle on the heights, the deep blue heaven
and the sailing clouds. Is it not worth some labour to gain command
of such a scene? But the delight it imparts is heightened by the
fact that we did not come expressly to see it; we came to instruct
ourselves about the glacier, and this high enjoyment is an incident
of our labour. You will find it thus through life; without honest
labour there can be no deep joy.
§ 17. _The Talèfre and the Jardin. Work among the Crevasses._
133. And now let us descend to the Mer de Glace, for I want to take
you across the glacier to that broken ice-fall the origin of which we
have not yet seen. We aim at the farther side of the glacier, and to
reach it we must cross those dark stripes of débris which we observed
from the heights. Looked at from above, these moraines seemed flat,
but now we find them to be ridges of stones and rubbish, from twenty
to thirty feet high.
134. We quit the ice at a place called the Couvercle, and wind round
this promontory, ascending all the time. We squeeze ourselves through
the _Égralets_, a kind of natural staircase in the rock, and soon
afterwards obtain a full view of the ice-fall, the origin of which we
wish to find. The ice upon the fall is much broken; we have pinnacles
and towers, some erect, some leaning, and some, if we are fortunate,
falling like those upon the Glacier des Bois; and we have chasms from
which issues a delicate blue light. With the ice-fall to our right
we continue to ascend, until at length we command a view of a huge
glacier basin, almost level, and on the middle of which stands a
solitary island, entirely surrounded by ice. We stand at the edge of
the _Glacier du Talèfre_, and connect it with the ice-fall we have
passed. The glacier is bounded by rocky ridges, hacked and torn at
the top into teeth and edges, and buttressed by snow fluted by the
descending stones.
135. We cross the basin to the central island, and find grass and
flowers at the place where we enter upon it. This is the celebrated
_Jardin_, of which you have often heard. The upper part of the Jardin
is bare rock. Close at hand is one of the noblest peaks in this
portion of the Alps, the Aiguille Verte. It is between thirteen and
fourteen thousand feet high, and down its sides, after freshly-fallen
snow, avalanches incessantly thunder. From one of its projections a
streak of moraine starts down the Talèfre; from the Jardin also a
similar streak of moraine issues. Both continue side by side to the
top of the ice-fall, where they are engulphed in the chasms. But at
the bottom of the fall they reappear, as if newly emerging from the
body of the glacier, and afterwards they continue along the Mer de
Glace.
136. Walk with me now alongside the moraine from the Jardin down
towards the ice-fall. For a time our work is easy, such fissures as
appear offering no impediment to our march. But the crevasses become
gradually wider and wilder, following each other at length so rapidly
as to leave merely walls of ice between them. Here perfect steadiness
of foot is necessary a slip would be death. We look towards the fall,
and observe the confusion of walls and blocks and chasms below us
increasing. At length prudence and reason cry "Halt!" We may swerve
to the right or to the left, and making our way along crests of ice,
with chasms on both hands, reach either the right lateral moraine or
the left lateral moraine of the glacier.
§ 18. _First Questions regarding Glacier Motion. Drifting of Bodies
buried in a Crevasse._
137. But what are these lateral moraines? As you and I go from day
to day along the glaciers, their origin is gradually made plain. We
see at intervals the stones and rubbish descending from the mountain
sides and arrested by the ice. All along the fringe of the glacier
the stones and rubbish fall, and it soon becomes evident that we
have here the source of the lateral moraines.
138. But how are the medial moraines to be accounted for? How does
the débris range itself upon the glacier in stripes some hundreds
of yards from its edge, leaving the space between them and the edge
clear of rubbish? Some have supposed the stones to have rolled
over the glacier from the sides, but the supposition will not bear
examination. Call to mind now our reasoning regarding the excess of
snow which falls above the snow-line, and our subsequent question,
How is the snow disposed of. Can it be that the entire mass is moving
slowly downwards? If so, the lateral moraines would be carried along
by the ice on which they rest, and when two branch glaciers unite
they would lay their adjacent lateral moraines together to form a
medial moraine upon the trunk glacier.
139. There is, in fact, no way that we can see of disposing of the
excess of snow above the snow-line; there is no way of making good
the constant waste of the ice below the snow-line; there is no way of
accounting for the medial moraines of the glacier, but by supposing
that from the highest snow-fields of the Col du Géant, the Léchaud,
and the Talèfre, to the extreme end of the Glacier des Bois, the
whole mass of frozen matter is moving downwards.
140. If you were older, it would give me pleasure to take you up
Mont Blanc. Starting from Chamouni, we should first pass through
woods and pastures, then up the steep hill-face with the Glacier des
Bossons to our right, to a rock known as the _Pierre Pointue_; thence
to a higher rock called the _Pierre l'Échelle_, because here a ladder
is usually placed to assist in crossing the chasms of the glacier.
At the Pierre l'Échelle we should strike the ice, and passing under
the Aiguille du Midi, which towers to the left, and which sometimes
sweeps a portion of the track with stone avalanches, we should cross
the Glacier des Bossons; amid heaped-up mounds and broken towers of
ice; up steep slopes; over chasms so deep that their bottoms are hid
in darkness.
141. We reach the rocks of the Grands Mulets, which form a kind
of barren islet in the icy sea; thence to the higher snow-fields,
crossing the _Petit Plateau_, which we should find cumbered by blocks
of ice. Looking to the right, we should see whence they came, for
rising here with threatening aspect high above us are the broken
ice-crags[B] of the Dôme du Goûté. The guides wish to pass this place
in silence, and it is just as well to humour them, however much you
may doubt the competence of the human voice to bring the ice-crags
down. From the Petit Plateau a steep snow-slope would carry us to the
Grand Plateau, and at day-dawn I know nothing in the whole Alps more
grand and solemn than this place.
[B] Named _séracs_ from their resemblance in shape and colour to an
inferior kind of curdy cheese called by this name at Chamouni.
142. One object of our ascent would be now attained; for here at the
head of the Grand Plateau, and at the foot of the final slope of Mont
Blanc, I should show you a great crevasse, into which three guides
were poured by an avalanche in the year 1820.
[Illustration: CREVASSE ON GRAND PLATEAU.]
143. Is this language correct? A crevasse hardly to be distinguished
from the present one undoubtedly existed here in 1820. But was it
the identical crevasse now existing? Is the ice riven here to-day
the same as that riven fifty-one years ago? By no means. How is this
proved? By the fact that more than forty years after their interment,
the remains of those three guides were found near the end of the
Glacier des Bossons, many miles below the existing crevasse.
144. The same observation proves to demonstration that it is the ice
near the _bottom_ of the higher névé that becomes the _surface-ice_
of the glacier near its end. The waste of the surface below the
snow-line brings the deeper portions of the ice more and more to the
light of day.
145. There are numerous obvious indications of the existence of
glacier motion, though it is too slow to catch the eye at once.
The crevasses change within certain limits from year to year, and
sometimes from month to month; and this could not be if the ice did
not move. Rocks and stones also are observed, which have been plainly
torn from the mountain sides. Blocks seen to fall from particular
points are afterwards observed lower down. On the moraines rocks
are found of a totally different mineralogical character from those
composing the mountains right and left; and in all such cases strata
of the same character are found bordering the glacier higher up.
Hence the conclusion that the foreign boulders have been _floated_
down by the ice. Further, the ends or "snouts" of many glaciers act
like ploughshares on the land in front of them, overturning with slow
but merciless energy huts and chalets that stand in their way. Facts
like these have been long known to the inhabitants of the High Alps,
who were thus made acquainted in a vague and general way with the
motion of the glaciers.
§ 19. _The Motion of Glaciers. Measurements by Hugi and Agassiz.
Drifting of Huts on the Ice._
146. But the growth of knowledge is from vagueness towards precision,
and exact determinations of the rate of glacier motion were soon
desired. With reference to such measurements one glacier in the
Bernese Oberland will remain forever memorable. From the little town
of Meyringen in Switzerland you proceed up the valley of Hasli, past
the celebrated waterfall of Handeck, where the river Aar plunges into
a chasm more than 200 feet deep. You approach the Grimsel Pass, but
instead of crossing it you turn to the right and follow the course of
the Aar upwards. Like the Rhone and the Arveiron, you find the Aar
issuing from a glacier.
147. Get upon the ice, or rather upon the deep moraine shingle which
covers the ice, and walk upwards. It is hard walking, but after
some time you get clear of the rubbish, and on to a wide glacier
with a great medial moraine running along its back. This moraine is
formed by the junction of two branch glaciers, the Lauteraar and the
Finsteraar, which unite at a promontory called the Abschwung to form
the trunk glacier of the Unteraar.
148. On this great medial moraine in 1827 an intrepid and
enthusiastic Swiss professor, Hugi, of Solothurm (French Soleure),
built a hut with a view to observations upon the glacier. His hut
moved, and he measured its motion. In the three years--from 1827 to
1830--it had moved 330 feet downwards. In 1836 it had moved 2,354
feet; and in 1841 M. Agassiz found it 4,712 feet below its first
position.
149. In 1840, M. Agassiz himself and some bold companions took
shelter under a great overhanging slab of rock on the same moraine,
to which they added side walls and other means of protection. And
because he and his comrades came from Neufchâtel, the hut was called
long afterwards the "Hôtel des Neuchâtelois." Two years subsequent
to its erection M. Agassiz found that the "hotel" had moved 486 feet
downwards.
§ 20. _Precise Measurements of Agassiz and Forbes. Motion of a
Glacier proved to resemble the Motion of a River._
150. We now approach an epoch in the scientific history of glaciers.
Had the first observers been practically acquainted with the
instruments of precision used in surveying, _accurate_ measurements
of the motion of glaciers would probably have been earlier executed.
We are now on the point of seeing such instruments introduced almost
simultaneously by M. Agassiz on the glacier of the Unteraar, and by
Professor Forbes on the Mer de Glace. Attempts had been made by M.
Escher de la Linth to determine the motion of a series of wooden
stakes driven into the Aletsch glacier, but the melting was so
rapid that the stakes soon fell. To remedy this, M. Agassiz in 1841
undertook the great labour of carrying boring tools to his "hotel,"
and piercing the Unteraar glacier at six different places to a depth
of ten feet, in a straight line across the glacier. Into the holes
six piles were so firmly driven that they remained in the glacier for
a year, and in 1842 the displacements of all six were determined.
They were found to be 160 feet, 225 feet, 269 feet, 245 feet, 210
feet, and 125 feet, respectively.