e same shape and weight, they at last ascertained the law of
descent. This was an important achievement, because, having become
familiar with the precise rate of descent at all depths, they were
enabled to tell very nearly when the ball ceased to carry out the line,
and when it began to go out in obedience to the influence of deep-sea
currents. The greatest depth reached by Brooke's sounding-line is said
to have been a little under five miles in the North Atlantic.

The value of investigations of this kind does not appear at first sight,
to unscientific men. But those who have paid even a little attention to
the methods and processes by which grand discoveries have been made, and
useful inventions have been perfected, can scarcely have failed to come
to the conclusion that _the search after_ TRUTH, _pure and simple, of
any kind, and of every kind, either with or without reference to a
particular end_, is one of the most useful as well as elevating pursuits
in which man can engage.

_All_ truth is worth knowing and labouring after. No one can tell to
what useful results the discovery of even the smallest portion of truth
may lead. Some of the most serviceable and remarkable inventions of
modern times have been the result of discoveries of truths which at
first seemed to have no bearing whatever on those inventions. When
James Watt sat with busy reflective mind staring at a boiling kettle,
and discovered the expansive power of steam, no one could have for a
moment imagined that in the course of years the inventions founded on
the truth then discovered would result in the systematic driving of a
fleet of floating palaces all round the world at the rate of from twelve
to fifteen or twenty miles an hour! Instances of a similar kind might
be multiplied without end. In like manner, deep-sea sounding may lead
to great, as yet unimagined, results. Although yet in its infancy, it
has already resulted in the discovery of a comparatively shallow plateau
or ridge in the North Atlantic Ocean, rising between Ireland and
Newfoundland; a discovery which has been turned to practical account,
inasmuch as the plateau has been chosen to be the bed of our electric
telegraph between Europe and America. The first Atlantic cable was laid
on it; and although that cable suffered many vicissitudes at first, as
most contrivances do in their beginnings, communication between the two
continents was successfully established. Soundings taken