Introduction

EDITORIAL NOTE.

Although in some respects more technical in their subjects and style than Darwin's "Journal," the books here reprinted will never lose their value and interest for the originality of the observations they contain. Many parts of them are admirably adapted for giving an insight into problems regarding the structure and changes of the earth's surface, and in fact they form a charming introduction to physical geology and physiography in their application to special domains. The books themselves cannot be obtained for many times the price of the present volume, and both the general reader, who desires to know more of Darwin's work, and the student of geology, who naturally wishes to know how a master mind reasoned on most important geological subjects, will be glad of the opportunity of possessing them in a convenient and cheap form.

The three introductions, which my friend Professor Judd has kindly furnished, give critical and historical information which makes this edition of special value.

G.T.B.

THE STRUCTURE AND DISTRIBUTION OF CORAL REEFS.

CRITICAL INTRODUCTION.

A scientific discovery is the outcome of an interesting process of evolution in the mind of its author. When we are able to detect the germs of thought in which such a discovery has originated, and to trace the successive stages of the reasoning by which the crude idea has developed into an epoch-making book, we have the materials for reconstructing an important chapter of scientific history. Such a contribution to the story of the "making of science" may be furnished in respect to Darwin's famous theory of coral-reefs, and the clearly reasoned treatise in which it was first fully set forth.

The subject of corals and coral-reefs is one concerning which much popular misconception has always prevailed. The misleading comparison of coral-rock with the combs of bees and the nests of wasps is perhaps responsible for much of this misunderstanding; one writer has indeed described a coral-reef as being "built by fishes by means of their teeth." Scarcely less misleading, however, are the references we so frequently meet with, both in prose and verse, to the "skill," "industry," and "perseverance" of the "coral-insect" in "building" his "home." As well might we praise men for their cleverness in making their own skeletons, and laud their assiduity in filling churchyards with the same. The polyps and other organisms, whose remains accumulate to form a coral-reef, simply live and perform their natural functions, and then die, leaving behind them, in the natural course of events, the hard calcareous portions of their structures to add to the growing reef.

While the forms of coral-reefs and coral-islands are sometimes very remarkable and worthy of attentive study, there is no ground, it need scarcely be added,