When I 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 3,000 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.