but vital activity.

Happily, however, better evidence in proof of the organic nature of the
_Globigerinoe_ than that of analogy is forthcoming. It so happens that
calcareous skeletons, exactly similar to the _Globigerinoe_ of the chalk,
are being formed, at the present moment, by minute living creatures,
which flourish in multitudes, literally more numerous than the sands of
the sea-shore, over a large extent of that part of the earth's surface
which is covered by the ocean.

The history of the discovery of these living _Globigerinoe_, and of the
part which they play in rock building, is singular enough. It is a
discovery which, like others of no less scientific importance, has
arisen, incidentally, out of work devoted to very different and
exceedingly practical interests. When men first took to the sea, they
speedily learned to look out for shoals and rocks; and the more the
burthen of their ships increased, the more imperatively necessary it
became for sailors to ascertain with precision the depth of the waters
they traversed. Out of this necessity grew the use of the lead and
sounding line; and, ultimately, marine-surveying, which is the recording
of the form of coasts and of the depth of the sea, as ascertained by the
sounding-lead, upon charts.

At the same time, it became desirable to ascertain and to indicate the
nature of the sea-bottom, since this circumstance greatly affects its
goodness as holding ground for anchors. Some ingenious tar, whose name
deserves a better fate than the oblivion into which it has fallen,
attained this object by "arming" the bottom of the lead with a lump of
grease, to which more or less of the sand or mud, or broken shells, as
the case might be, adhered, and was brought to the surface. But, however