The earth

Preface

r

Both the size and the purpose of this work are incompatible with the notion of its being a detailed description of the Earth, or a particular exposition of any one of the many sciences into which it is found necessary to divide anything like a thorough knowledge of our planet. The first of these must be sought for in the common works on descriptive geography, and the second lie scattered through the many volumes in which the doctrines of physical science, and the investigation and description of physical agencies and their effects, are treated. To have attempted to embody one of those sciences would have been attempting to do anew that which has already been more fully, and therefore more perfectly, done, than if every page of the following sections had been devoted to it. To have drawn up a mere list of those sciences and their subjects, would have been presenting feeble-itovigs instead of the bundle of rods, and without *that cord of unity to which alone the strength of the bundle is owing.

Therefore, I have attempted to supply that which is not found in any one book, and probably not in any number of books, which have been hitherto published. I have attempted to give as clear and comprehensive a view as possible of the earth, considered as a whole, having equal regard to the causes or agencies which produce

4 PREFACE.

the more general terrestrial phenomena, and to the things in which, and the places where, these phenomena present themselves. For this purpose I have first attempted to show the great practical advantages which are derived from a proper knowledge of the earth, and the characters and relations of the several seas and lands of which its surface is composed. I have next attempted to show the great assistance which we derive from a really good map of the world in learning those details that form the basis on which the more argumentative and inferential part of the subject is founded. Having done so, I have cast a glance over the various lands, and the seas by which they are separated ; pointing out the general character of each of the great natural divisions of the land, and hinting how these work together in bringing about all that occurs by natural causes. This being done, I have given some account of the agents and instruments which are chiefly influential in producing terrestrial phenomena ; and I need not apprise any one who is acquainted with the subject, that the grand agent is the sun, and the grand instruments are, the air of the atmosphere and the water of the sea, whiclmd-istribute the solar action over the surface of the earth, producing a state of things so very different from what would be if the air and the waters were as locally chained by gravitation as the more solid parts of the globe.

In treating of solar action, and its distribution, which form the grand elements of a proper understanding of the earth as the field of growth and the abode of life, which is the true and the useful understanding of the matter, I have thought proper, and have, indeed, felt it necessary, to

PREFACE. o

proceed something in the way of analysis ; and if, in the course of this analysis, one or two views have been opened up of the power and grandeur of some of the instruments of God's working which are new to the reader, he must not be startled at the vast height and the immensity of distance to which they beckon him to look ; for we may rest assured that, in all cases where we can carry our analysis of nature as near as we can to the primal secondary cause, the mind feels itself trenching upon the bourne of infinitude, and our philosophy falls down in humble adoration before the throne, confesses its Maker, and exults and triumphs in the confession.

With a view to simplify this very sublime and very important matter as much as possible, I have first considered what would be the general effect pf the sun upon a hemisphere of the earth, if both sun and earth were at perfect rest, situated at the same distance from each other as they are now, and if the sun-beams had precisely the same nature as they have at present, but that there were no moveable air or water, or any marked difference of surface, to modify their action. This is the elementary view, and the determination of it is a matter of geometry, partaking of all the certainty of that science ; and this being once understood, the observed departures from it of themselves lead us to the investigation of their causes.

The full statement, or even the mere enumeration of all those causes, more especially the local ones, would have been incompatible with the space to which I was necessarily restricted ; and therefore I have considered chiefly the two general sources of modification, — the daily rota- 1*

O PREFACE.

tion of the earth upon its own axis, and its annual motion round the sun in its orbit. By means of these, I have been enabled to state generally the effect which is produced by the reciprocal actions of the two hemispheres upon each other at different seasons of the year; and also, how those actions are farther modified by some of the more remarkable characters of the extensive divisions of the land ; and thus I have been enabled to give a sort of general view of the phenomena of the year, though I fear it will be found both hasty and incomplete. My object is not, however, to teach scholastically, but to entice the reader to learn for himself practical!}^ pleasantly, and profitably ; — to stimulate the desire of knowledge, and to simplify the means of acquiring it, as well for the satisfaction and superiority which true knowledge gives us in this world, as for the confirmation which it affords of the fulfilment of our best hopes when to us this world shall be no more.

Robert Mtjdie.

ANALYSIS OF THE CONTENTS.

Section I. Preliminary Remarks

Advantages of a Knowledge of the Earth — Extent of that Knowledge — Method of studying complicated Subjects — Collateral Sciences- — Geography, Geology, Meteorology — General Instruction from the subject .... p. 11 — 30

SECTION II. GEOGRAPHICAL REPRESENTATION, OR MAP, OP THE EARTh's SURFACE

Representation of the Earth — Globes — Maps — Stereographic Projection — Advantages of this Projection — Positions on the Globe— The Hemispheres — The Details — Uses of the Map,— In History, in General Knowledge . . p. 31 — 44

Section III. Form, Magnitude, And General Features Of The Earth

Figure of the Earth — Irregularities of that Figure — Different means of ascertaining these — Distribution of the Zones — Advantages of this Distribution — Extent of the Earth's Surface — Relative Portions of Sea and Land — Comparison of the Two Hemispheres, as divided by the Circular Boundaries of an Ordinary Map of the World — Northern Coasts of Asia and Europe — Characters of the Countries there — "West Coast of Europe — The Mediterranean, and its Basin — General Characters, and Action of this Basin — Seasonal Migration p. 45 — 80

ANALYSIS OF THE CONTENTS.

Section IV

GENERAL FEATURES OF THE EARTH. EASTERN CONTINENT

CONTINUED.

Northern Africa — Mountains of Atlas — The Desert of Sahara — Character and Action of this Desert — Progress of Ruin — Formation of Sand Banks — Decomposition of Mountains — Antiquity of the Earth — Ancient Egyptian Temples and Statues — Antiquity of the Desert — Comparison of the Wild and the Wilderness — Western Africa — The Fertile

Country there — Flooding of Rivers — Southern Africa

Eastern Africa — Southern Asia — Australia — Reciprocating Action between Southern Asia, and Africa and Australia , p, 81—110

Section V

CENERAE FEATURES OF THE EARTH. AMERICA.

North America — Its Boundaries and Divisions — The Great Central Valley — The Mississippi — Vegetables and Animals of the Mississippi Valley — Other Regions of North America — Mexico — The Table Land of Mexico— The Progress of Drought — The Mexican Andes — The Isthmus, p. 1 1 1 — 128

Section VI

GENERAL FEATURES OF THE EARTH. AMERICAN CONTINENT

CONTINUED.

General Characters of South America — The Andes — And other Mountain Ridges — The Amazon and its Valley — The Orinoco — La Plata — Plains of Paraguay — The Pampas p. 129—147

Section VII. Brief Abstract Of The Earth's Features

Recapitulation — Interruptions of Sea and Land— Instances of

ANALYSIS OF THE CONTENTS. 9

those Interruptions — In North America — Tn South America — in the Eastern Continent . . . . . . p. 148 — 155

Section VIII

ARESTS .\SD IKSTRUMESTS IN THE MORE GENERAL PHE- NOBEE-ITA OF THE EARTH.

Duty of a Popular Writer — Advantages of Popular Writing on Scientific Subjects — The Natural Desire of Knowledge — The Relation between Action and Resistance — Aggregation as opposed to Gravitation — Action of the Sun — Principle of Growth — The System of Matter — Swiftness of Light — Of Thought — Action of Heat — Seasonal Action — Action of the Air — Action of Air on Water — Effect of Motion in the Sun-beams p. 156 — 1S8

Section IX

MODIFICATION OF THE St's's ACTION BY THE FIGfRE OF THE EARTH.

Means of estimating the Sun's Action — Temperatures of Different Latitudes — Advantages of the Spherical Form of

the Earth — Atmospheric Modifications of Solar Action

Refraction — Reflection — Colour — Atmospheric Refraction

— Partial Reflection Sun-beams on Water On Rich

Surfaces — On Bare Surfaces — Grandeur of Creation

SECTION X. EFFECTS OF THE EARTh's ROTATION

General Effect of the Earth's Rotation — Looking at and Looking from — Comparison of Rotation and Rest — Advantages of Rotation — Comparison of the Earth and Moon — Compound Motions — Motion in Rotation, and in Latitude — Air moving to the Equator — Moving from — Causes of Motion in the Air — The Sun over the Equator — Characters of Different Latitudes in this Case — Illustrations

10 ANALYSIS OF THE CONTENTS.