The telegraph manual: a complete history and description of the semaphoric, electric and magnetic telegraphs of Europe, Asia, Africa, and America, ancient and modern.

ELEMENTS OF THE OCEAN. 653
the arm, c, a slight inclination, which, with the friction of the
water on the line, holding it back, guards against premature
detachment.
It is obvious that the sensitiveness of this detaching apparatus, will depend upon the relative positions of those three
points; for the arm, c, may be regarded as a lever of the
second order with its fulcrum at D; the gravity of the shot as
the power acting upon the resistance of the line. So that, by
increasing or diminishing the distance of the ring, H, from the
pin, D, the detachment is rendered more or less difficult.
In order that change of position in the arm, c, as it yields
to the pull of the shot in the act of detaching, may not interfere, it is so made as to permit the ring to slip back as the arm
inclines, as shown by fig. 3.
On soft bottom it should work as well as on hard, for it is
only necessary that there shall be a retardation of the descent
of the rod, while the heavier shot continues to descend into
the mud, to cause the turning of the arm and discharge the
shot.
Before using the instrument, the operator may test its sensitiveness and adapt it to the depth of the water; in deep
sounding, it should be so delicately adjusted, as to act upon the
slightest touch, and should be eased down for the first fifty
fathoms, or more.
The quills, Q q, are cut as per figure, and are placed with
the cut ends downward, and then several of them are wedged
into the cell or holder. The advantages of this arrangement
are, we have more abundant specimens than an ordinary arming will bring up, and then we have the gratification of having
them properly examined by the microscope."
With this lead the deep sea has been fathomed, and its bottom exposed to man, and upon its examination by the microscope the supposed earth has been found to be the remains of
the minute inhabitants, or the organisms of the sea.
THE ELEMENTS OF THE OCEAN.
On the subject of Ocean telegraphy, Lieut. Maury thus
writes: "It is an established fact that there is no running
water at the bottom of the deep sea. The agents which disturb the equilibrium of the sea, giving violence to its waves
and force to its currents, all reside near or above its surface;
none of them have their home in its depths. These agents are
its inhabitants, the moon, the winds, evaporation and precipitation, with changes of temperature-such as heating here, and
cooling there.