20,000 LHAGUHS UNDER THE SEAS. TT
“Just so, sir.”
‘Then unless you quite fill the Nautilus, I do not see
how you can draw it down to those depths.”
“Professor, you must not confound statics with dy-
namics, or you will be exposed to grave errors. There is
very little labor spent in attaining the lower regions of the
ocean, for all bodies have a tendency to sink. WhenI
wanted to find out the necessary increase of weight required
to sink the Nautilus, I had only to calculate the reduction
of volume that sea-water acquires according to the depth.”
«That is evident.”
“‘Now, if water is not absolutely incompressible, it is at
least capable of very slight compression. Indeed, after the
most recent calculations this reduction is only .000436 of
an atmosphere for each thirty feet of depth. If we want
to sink 3000 feet, I should keep. account of the reduction
of bulk under a pressure equal to that of a column of water
of a thousand feet. The calculation is easily verified.
Now, I have supplementary reservoirs capable of holding a
hundred tons. ‘Therefore I can sink to a considerable
depth. When I wish to rise to the level of the sea, I only
let off the water, and empty all the reservoirs if I want the
Nautilus to emerge from the tenth part of her total ca-
pacity.” .
I had nothing to object to these reasonings.
“‘T admit your calculations, Captain,” I replied; ‘I
should be wrong to dispute them since daily experience
confirms them; but I foresee a real difficulty in the way.”
‘¢ What, sir?”
‘*When you are about 1000 feet deep, the walls of the
Nautilus bear a pressure of 100 atmospheres. If, then,
just now you were to empty the supplementary reservoirs,
to lighten the vessel, and to go up to the surface, the
pumps must overcome the pressure of 100 atmospheres,
which is 1500 lbs. per square inch. From that a power—”
«That electricity alone can give,” said the captain,