A Description of Active and Extinct Volcanos, of Earthquakes, and of Thermal Springs

with regard to the characters and situation of the rocks which owe their origin to subterraneous fire.

I have only further to add, that the remarks, made at the commencement of the First Lecture, with respect to the little attention that has been paid in Great Britain to the Department of Geology which forms the subject of this work, must be understood as applying solely to that portion of it which relates to Products confessedly Volcanic; for in no country have more important lights been thrown on the nature of Trap and Basaltic Districts, than by the labours of Dr. Macculloch and of other English Geologists*; to some of whom I feel personally indebted, either for much of the information which forms the groundwork of such an inquiry, or for the friendly assistance afforded me in the prosecution of it.

See particularly the Memoir on the Coast of Antrim, by my friends the Rev. W. Buckland and W. Conybeare, in the third volume of the Geological Transactions, supplementary to Dr. Berger's paper on the same district.

PREFACE

TO THE SECOND EDITION.

Ir any apology be thought requisite for reviving at the present time a Treatise that has for many years past been out of print, the mere reference to its present as compared with its original bulk may, it is conceived, suggest reasons that will appear satisfactory.

That this increase in its size has not arisen from a more diffuse or discursive mode of writing, will be manifest from a very cursory examination of its contents; indeed, it may be perceived, that the facts are presented in a more condensed form than heretofore; that much of what appeared less relevant to the subject has been curtailed or omitted; and that every effort has been made by the Printer to economise space, by bringing the lines into closer juxtaposition, and by the substitution of a smaller type for the less important portion of the details.

Such, nevertheless, have been the accessions to the mass of our information on the subjects discussed in this Volume which the last twenty years have produced, that whereas in the former Edition the Descriptive Portion occupied only 352 loosely printed pages, in the present it has swollen to no less than 503; and that the General Remarks on Volcanic Phænomena, which were heretofore comprised within 80 pages, have now extended themselves to 110.

Moreover, a still further increase to the size of the volume has been occasioned by my regarding, as Departments of Volcanic Geology, Earthquakes and Thermal Springs, phænomena passed over in a very cursory manner in the former Edition, but occupying nearly 100 pages in the present.

In this extension of my design it would have been manifestly absurd to have retained the division into Lectures, in which form the original draft or outline of my Work was moulded : but it will be seen that the same arrangement of the materials is still persevered in, as being, it is conceived, convenient, both in enabling the Reader to grapple with the facts, before his mind is biassed with the hypotheses, and also in rendering the Volume capable of serving as a kind of Guide-book to the Explorers of Districts in which Volcanic phænomena occur abroad, no less than as a Storehouse of Facts for those who reason upon them at home.

In short, if in the imperfect and immature form in which it originally appeared-before the researches of Darwin, of Abich, of Elie de Beaumont, and of a whole host of other Geological travellers, had shed so much light upon the phænomena of Volcanos—my Work met with a favourable reception*, as well as a ready sale, it may be offered to the Public with some degree of confidence now, when the subject itself comes invested with a new interest, owing to the connexion between the present phænomena of Volcanos and the past as well as future Revolutions of our Planet, that has been substantiated through the important contributions which the persons above-mentioned and so many other of their fellowlabourers have rendered to Science.

By thus drawing largely from the Investigations of others, as well as from the Memoirs on Volcanic Geology which I have myself communicated to various Societies since the first publication of this Treatise, it has been my endeavour to incorporate with the original materials whatever had been added of any value to our stock of knowledge on this subject during the years that have since elapsed; and although I have not seen reason to abandon the views with which I started, either with respect to the probable cause of volcanic action, or the mode of its operation, my readers, it is conceived, will find the means of correcting my errors on these points placed within their reach, by the faithful report of the phænomena themselves which is presented to their consideration.

* See especially the Edinburgh Review for March 1827.

In a word, whilst avoiding, as much as possible, to challenge controversy, I have been far from keeping out of sight, and have rather aimed at giving a prominence to, such statements and expositions of facts as seemed least in accordance with the Geological opinions now in vogue, thus labouring, so far as in me lies, to correct that one-sidedness of mental vision which is apt to be engendered, by contemplating exclusively.one class of geological agents, and by regarding the truths of Science under certain particular aspects.

Above all, it has been my wish to attach to Chemical considerations their just and proper weight, confident that if I can succeed in so doing, I shall be rewarded by the satisfaction of having enlisted in the cause of Geology a potent and too much neglected Ally, even though it should, as is very possible, supply weapons to others for the demolition of the theories that I have myself aimed at constructing by its aid.

Nov. 30, 1847.