November 13, 1914] 



SCIENCE 



711 



only to the aviator but to those vs^ho may be 

 under him; a simile suggested by his obser- 

 vation that geology is " a science involving 

 long excursions into space." It is to be hoped 

 that in his contributions to higher education 

 Professor Daly will keep this risk constantly 

 before his readers. 



His statement that " science is built on a 

 long succession of mistakes " is inexact. Very 

 serious mistakes have been made in the past, 

 and obviously are being made still by those 

 who are earnestly endeavoring to build it up, 

 but it is to be hoped that very little of the 

 structure of modern science is built upon mis- 

 takes. It is true as the author says that " their 

 recognition means progress." Most surely, 

 perhaps, when we recognize our own, for " thus 

 we rise on stepping stones of our dead selves 

 to higher things." 



The author seems to be outside of petro- 

 graphical conceptions when he imagines that 

 " science is drowning in facts." The solid 

 facts of petrology should furnish the best 

 building material for a scientific structure, 

 as well as for a foundation, and are not in 

 such a flux as his metaphor suggests. There 

 are many evidences in the book before us that 

 its author confuses facts and subjective con- 

 ceptions or hypotheses about them; indeed, he 

 closes the introduction with the statement that 

 " The ' facts ' of to-day are the hypotheses of 

 yesterday," and he demonstrates his confidence 

 in this assertion by citing as facts in one 

 chapter what were his own hypotheses in a 

 previous one. 



In his zealous endeavor to advance the sci- 

 ence of petrology Professor Daly has the earn- 

 est sympathy of his fellow workers, however 

 much some of them may disagree with him 

 as to his methods of thought and of presen- 

 tation, or as to his assumptions and conclu- 

 sions, but the present writer is somewhat at a 

 loss as to how one should interpret Professor 

 Daly's statement that " the best sympathy is 

 expressed in constructive criticism." If this 

 means that the construction should be an 

 elaboration of his hypotheses and theories, 

 then the reviewer regrets that his sympathy 

 is not of that kind. However, if constructive 



criticism consists in the presentation of other 

 hypotheses, built with the aid of the imagina- 

 tion on other premises, which seem to the 

 writer to be more secure and more in accord 

 with modern conceptions regarding the physics 

 of the earth and the essential characteristics 

 of igneous rocks and their molten magmas, 

 then he would present Professor Daly with 

 the views expressed in the writer's recent lec- 

 tures on volcanism at Tale University as a 

 token of his sympathy, and would ask him to 

 look upon the present criticism of his work 

 on "Igneous Eocks and Their Origin" as an 

 evidence of the serious concern which the 

 writer feels for the science which both of us 

 are striving to promote, and of his sense of 

 duty in pointing out what seem to the writer 

 some of the mistakes of method employed 

 with such dangerous effectiveness by the 

 brilliant but, as it seems to the writer, mis- 

 taken author of the volume in hand. 



Since the book is an elaboration of papers 

 already published by the author, which are 

 familiar to most students of petrology, it will 

 not be necessary to state at length the contents 

 of the work which are given in a brief ab- 

 stract in the first chapter, from which may be 

 gotten more definite ideas of the author's 

 views than are obtainable in some instances 

 from the involved discussions in subsequent 

 chapters. Moreover, the book is so full of 

 statements, citations and tabulated material, 

 much of which is open to criticism and debate, 

 that it would require an exhaustive treatise to 

 discuss the whole work thoroughly. The 

 volume represents a great amount of energy 

 and thought expended through years of study 

 and speculation, evidences of which may be 

 found in extensive tables compiled to illustrate 

 the author's hypotheses, as well as in abundant 

 bibliographic references which must represent 

 but a small part of the author's researches 

 into the literature of petrology, a large part 

 of which would seem to be of little value for 

 his purpose. 



It seems to the writer that the most funda- 

 mental feature of the book is the mistaken 

 method employed by its author in his at- 

 tempts to solve the problems of volcanism. 



