Outlines of the Earths History | Page 5

interpret
the history of the earth. In fact, day by day, with the advance of
learning, we come more clearly to perceive that all the processes of
Nature are in a way related to each other, and that in proportion as we
understand any part of the great mechanism, we are forced in a manner
to comprehend the whole. In other words, we are coming to understand
that these divisions of the field of science depend upon the limitations
of our knowledge, and not upon the order of Nature itself. For the
purposes of education it is important that every one should know
something of the great truths which each science has disclosed. No
mortal man can compass the whole realm of this knowledge, but every
one can gain some idea of the larger truths which may help him to
understand the beauty and grandeur of the sphere in which he dwells,
which will enable him the better to meet the ordinary duties of life, that

in almost all cases are related to the facts of the world about us. It has
been of late the custom to term this body of general knowledge which
takes account of the more evident facts and important series of
terrestrial actions physiography, or, as the term implies, a description of
Nature, with the understanding that the knowledge chosen for the
account is that which most intimately concerns the student who seeks
information that is at once general and important. Therefore, in this
book the effort is made first to give an account as to the ways and
means which have led to our understanding of scientific problems, the
methods by which each person may make himself an inquirer, and the
outline of the knowledge that has been gathered since men first began
to observe and criticise the revelations the universe may afford them.
CHAPTER II.
WAYS AND MEANS OF STUDYING NATURE.
It is desirable that the student of Nature keep well in mind the means
whereby he is able to perceive what goes on in the world about him. He
should understand something as to the nature of his senses, and the
extent to which these capacities enable him to discern the operations of
Nature. Man, in common with his lower kindred, is, by the mechanism
of the body, provided with five somewhat different ways by which he
may learn something of the things about him. The simplest of these
capacities is that of touch, a faculty that is common to the general
surface of the body, and which informs us when the surface is affected
by contact with some external object. It also enables us to discern
differences of temperature. Next is the sense of taste, which is limited
to the mouth and the parts about it. This sense is in a way related to that
of touch, for the reason that it depends on the contact of our body with
material things. Third is the sense of smell, so closely related to that of
taste that it is difficult to draw the line between the two. Yet through
the apparatus of the nose we can perceive the microscopically small
parts of matter borne to us through the air, which could not be
appreciated by the nerves of the mouth. Fourth in order of scope comes
the hearing, which gives us an account of those waves of matter that we
understand as sound. This power is much more far ranging than those

before noted; in some cases, as in that of the volcanic explosions from
the island of Krakatoa, in the eruption of 1883, the convulsions were
audible at the distance of more than a thousand miles away. The greater
cannon of modern days may be heard at the distance of more than a
hundred miles, so that while the sense of touch, taste, and smell
demand contact with the bodies which we appreciate, hearing gives us
information concerning objects at a considerable distance. Last and
highest of the senses, vastly the most important in all that relates to our
understanding of Nature, is sight, or the capacity which enables us to
appreciate the movement of those very small waves of ether which
constitute light. The eminent peculiarity of sight is that it may give us
information concerning things which are inconceivably far away; it
enables us to discern the light of suns probably millions of times as
remote from us as is the centre of our own solar system.
Although much of the pleasure which the world affords us comes
through the other senses, the basis of almost all our accurate knowledge
is reported by sight. It is true that what we have observed with our eyes
may be set forth in words, and thus find its way to the understanding
through the