The reason why : $b a careful collection of many hundreds of reasons for things which, though generally believed, are imperfectly understood. A book of condensed scientific knowledge for the million
John Stuart Mill · en
Amid all the wonders of nature which we have had occasion to
explain, there is none more startling than that which reveals
to our knowledge the fact that a flint stone consists of the
mineralised bodies of animals, just as coal consists of masses
of mineralised vegetable matter. The animals are believed to
have been infusorial animalculæ, coated with silicous shells,
as the wheat straw of to-day is clothed with a glassy covering
of silica. The skeletons of animalculæ which compose flint may
be brought under microscopic examination. Geologists have some
difficulty in determining their opinions respecting the relation
which these animalculæ bear to the flint stones in which they are
found. Whether the animalculæ, in dense masses, form the flint;
or whether the flint merely supplies a sepulchre to the countless
millions of creatures that, ages ago, enjoyed each a separate
and conscious existence, is a problem that may never be solved.
And what a problem! The buried plant being disentombed, after
having lain for ages in the bowels of the earth, gives us light
and warmth; and the animalcule, after a sleep of ages, dissolves
into the sap of a plant, and wraps the coat it wore, probably "in
the beginning, when God created the heavens and the earth, and
when the earth first brought forth living creatures," around the
slender stalk of waving corn!
1261. _Why is silica diffused over the stems of wheat, grasses, canes,
&c.?_
Because it affords strength, density, and durability, to structures
that are very light, and which, but for this beautiful provision, would
be exceedingly perishable.
[Verse: "For in this mountain shall the hand of the Lord rest, and
Moab shall be trodden down under him, even as straw is trodden down for
the dunghill."--ISAIAH XXV.]
1262. _Why is guano a productive manure?_
Because it contains, with other suitable elements, an abundance of the
_silicous skeletons of animalculæ_.
1263. _Why does a wheat-crop greatly exhaust the soil?_
Because, as well as the _carbon, and the salts_, which form the straw
and the grain, it draws off from the soil a great amount of _silica_.
1264. _Why is straw frequently used as a manure?_
Because it gives back, with other substances, a _considerable
proportion of silica_, in that form which adapts it to the use of the
succeeding crop.
1265. _Why is the structure of herbaceous plants less consolidated than
that of woody plants?_
Because, for the most part, herbaceous plants last only _a single
year_; they, therefore, do not require the enduring qualities of plants
that have to sustain the influences of the elements for a succession of
seasons.
1266. _Why are the stalks of plants of light structure generally
cylindrical?_