bellows, F, which gives entrance to the sea water. The springs shown
in the figure balance the hydraulic pressure. The tension of these
springs is regulated by the rod, H, according to the indications of
the scale of depths, I.

When the torpedo reaches too great a depth, the action of the springs
can no longer balance the increase of the hydraulic pressure, and the
accumulation of the charge in the rear causes the front to rise toward
the surface. When the torpedo reaches the surface, a contrary action
is produced.--_Revue Industrielle._

* * * * *




THE FIRST STEAMBOAT ON THE SEINE.


[Illustration: FIRST STEAMBOAT BUILT ON THE SEINE.]

The accompanying engraving represents the remarkable steamboat that
the unfortunate Marquis de Jouffroy constructed at Paris in 1816,
after organizing a company for the carriage of passengers on the
Seine. De Jouffroy, as well known, made the first experiment in steam
navigation at Lyons in 1783, but the inventor's genius was not
recognized, and he met with nothing but deception and hostility. With
the obstinacy of men of conviction, he did not cease to prosecute his
task. He assuredly had an inkling of the future in store for the
invention that he was offering to humanity.