SOME NEW BOOKS. 



Volcanoes : Past and Present. By Edward Hull, M.A., LL.D., F.R.S., 

 Examiner in Geology to the University of London. Contemporary Science Series. 

 London ; Walter Scott, 1892. 



This volume is published in good company ; it belongs to a series 

 which has hitherto well maintained its claim to represent the state 

 of contemporary science. It is not without other credentials, — the 

 author is a Fellow of the Royal Society, a doctor of laws, and was, 

 until lately, the Director of the Geological Survey of Ireland. We 

 shall therefore confidently expect to find in it many things both 

 new and true ; indeed, the author expressly promises in his preface 

 " the most recent conclusions regarding the phenomena and origin 

 of volcanic action," illustrated by "examples drawn from the districts 

 where these phenomena have been most carefully observed and 

 recorded under the light of modern geological science." A past 

 Director of Geological Survey, writing with these aims, may be 

 fairly expected to know something of the volcanic rocks of which 

 he makes frequent mention throughout the book, yet there is some- 

 thing in his use of terms which, as we read, begins to excite uneasy 

 suspicions, and leads us at last to consult the Appendix, in which is 

 given " A Brief Account of the Principal Varieties of Volcanic 

 Rocks." Let us examine this " in the light of modern geological 

 science." Whatever arguments can be adduced to prove that 

 granite is essentially a deep-seated rock, are equally applicable 

 in the case of gabbro. Every English geologist might have been 

 presumed to have known this much since the appearance of Professor 

 Judd's epoch-making work on " The Ancient Volcanoes of the 

 Highlands of Scotland," published so far back as 1874 ; yet on page 

 261 we read that gabbro is a volcanic rock, and a little later that 

 granite is not a volcanic rock. We regret that we are not favoured 

 with reasons for this distinction ; they would no doubt be interesting 

 in the hght of " Contemporary Science." We shall discover more 

 contemporary science in the " Tabular View of the Chief Igneous 

 and Volcanic Rocks " given in the Appendix : the well-known 

 sub-division into Basic, Intermediate and Acidic rocks is adopted, 

 but, altered and unaltered, volcanic and plutonic rocks are all 

 jumbled up together, as though each were a species of the same 

 value. But this is a trivial defect in comparison with graver errors ; 

 thus we find the Porphyrites placed in the Basic group, and the 

 Andesites, of which they are the altered equivalents, in the Inter- 

 mediate group, along with Syenite and Mica-trap, while Trachyte is 

 separated from its plutonic representative. Syenite, and placed with 

 the Acidic rocks in company with Domite and Phonolite. And this 

 is Contemporary Science ! 



Had the author only consulted Professor Judd's v/ork on 

 " Volcanoes," published in the International Science Series in 1885, 



2H 



