THE VOYAGE OF H.M.S. CHALLENGER. 
M ABSIIJ.I ON 
M * RINK 1>EPOSITi>. 
60 
depth n..ist be found. The St. Gothard in Switzerland is the highest mountain I have as 
yet v dh d, but as I have not its exact altitude, I will take the one nearest to our shores, 
viz.. Mount C'anigou, which Mr Cassini, while tracing the Meridian of the Royal Observa- 
tory of Paris, which is carried through the entire length of France, found to be 1400 
fathoms above the level of the sea. I have applied this rule to the depth where the 
b. uom begins to descend rapidly, and also to a spot where Mount Canigou begins to 
rise, to form a section, wherein one may see at a glance the connection between these two 
joints, equally distant from the greatest height of the mountain and the greatest depth 
• >: the sea. 1 This demonstration sufficiently proves, I think, that the unknown depth 
of the sea corresponds with the greatest height of the mountains on land, for it is easy 
to see that both are formed of superposed strata, lying at a certain ascending or 
descending angle.” 
Mursilli allowed himself to be carried away by his love of symmetry ; he does not 
adduce one fact in support of his theory on the depths of the sea. But his work, 
which is interesting in more than one respect, deserves to be quoted, because it 
reflects the ideas of the time in which it was written, and also because the section he 
gives is the first attempt to graphically represent the relief of the globe. Marsilli 
heb . dong with the most able seamen whom he had consulted, that the greatest depth 
• ‘ the Mediterranean was abreast of the island of Malta. The seamen had also observed 
that when the shores are high and vertical the sea is very deep. 
M i rsill i makes a few observations on the knowledge then possessed concerning the 
nature of the bottom of the sea. He believes that the basin of the sea was excavated 
“at the time of the creation, out of the same stone which we see in the strata of 
the earth, with the same interstices of clay to bind them together.” 2 He adds that 
we should not judge of the nature of the bottom by the materials which seamen bring 
uji in their soundings. They dredge almost always on a muddy bottom, and very 
rarely on a rocky one, because the latter is covered with slime, sand, sandy, earthy, 
and calcaicous concretions, and organic matter. These substances, he says, conceal 
• real bottom of the sea, and have been brought there by the action of the water; 
they lw; ys cover stony masses. “Lastly,” he adds, “to explain myself briefly, 
1 may compare the bed of the sea to a cask, which, having long held wine, seems 
from the inside to be made of dregs of tartar, though it is really of wood.” In the 
pr .f.! accompanying his work, he has marked with dotted lines the stony parts of the 
button ; he distinguishes those which are covered with fine sand or with a sandy con- 
glutination ; the part covered with fine sand is always that exposed to the How of rivers. 
. 1. Mire (M.irxilli, op. rit., pi. iii. p. 4, profile* or sections of the basin of the sea) shows the profile of Mount 
' i i. ) ■ mountain in the Pyrenees, the height of which is 14<K) fathoms, down to Cape Rose in Catalonia. 
I* ■ - : 1 is< tin • i for a distance of fi4 miles south-east, and at that point lies the abyss, which is as much below 
t 1 irf i ■: of the n a as the mountain is above it 3 Marsilli, op. cil., p. 14. 
