238 



SCIENCE. 



[N. S. Vol. II. No. 34. 



sions throughout the work. To cite these 

 instances in detail would require too much 

 space, but they will not fail to arrest the 

 attention of those familiar with the subject. 

 It is no doubt to the same fundamental 

 cause that the work owes its grave defects 

 in classification, a defect that appears even 

 in the title. Bitumen is the generic term 

 that includes all forms of petroleum and as- 

 phalt. Moreover, no distinction is made 

 between the peculiar use made by French 

 authors of the word asphalte as applied to 

 the asphaltic limestones and sandstones of 

 eastern France and Switzerland and the 

 use of the word to designate the solid form 

 of bitumen, in which latter use he has made 

 it the equivalent of ' asphalt ' in English. 

 The words naphtha and petroleum, and 

 petroleum and maltha, are also used inter- 

 changeably to some extent in some places 

 and with diiferent meanings in others, so 

 that throughout the work the use of these 

 words is not clear. This confusion arises 

 from a disregard of details that belong to 

 chemistry rather than to geology. . 



As a whole, the work possesses great 

 merits and grave defects ; especially is the 

 latter statement true in relation to Ameri- 

 can bitumen. The work should be read 

 with careful discrimination, which is much 

 to be regretted, as it will doubtless be 

 widely read in Europe, where its merits 

 will be much more apparent than its de- 

 fects. S. F. Peckham. 



The .Glacial Nightmare and tlie Flood. Hy SiE 

 Henry Howarth, K. C. I. E., M. P., F. 

 G. S., etc. 2 vols. Pp. 11-920. Samp- 

 son, Low, Marston & Co. 

 This volume is a manual of the facts and 

 changing opinions gathered and expressed 

 by the students of the superficial features of 

 Europe and America from the earliest days 

 of observation, and brings into prominence 

 the names of many excellent men formerly 

 overlooked or forgotten. The work is a fair 



history of the rise and decay of the theory 

 of floods, of the universalitj' and restriction 

 of iceberg action, of the origin and culmin- 

 ation of the glacial theory. Thus far the 

 author's views are only seen in the title. 

 On the subject of the unity of the glacial 

 period, the evidence is stated with the 

 writer's judgment favoring one general 

 period of cold. The astronomical theory of 

 the cause of the Ice Age is shown to be un- 

 sustained bj' the evidence. The cause of 

 glacial motion and the mechanical effects of 

 the. glaciers are discussed in a masterly 

 manner, with conclusions very acceptable 

 to most of us. The use of the doctrine of 

 an ice cap and its subsequent restriction to 

 continental areas is explained. But now 

 the work is directed against extreme views, 

 which have prevailed or are still dominant, 

 on the ground of want of evidence. In the 

 latter part of the work the writer ceases to 

 be the judicial historian and becomes the 

 philosopher, and explains some phenomena 

 of the drift, carefully analj'zed, by an appeal 

 to ' waves of translation,' a modification of 

 the doctrine of catastrophies in contra-dis- 

 tinction to the ideas of extreme uniformity 

 which often need modification. The work is 

 invaluable to the American student on ac- 

 count of giving him access to many of the 

 fathers of superficial geologj', whose works 

 are not ordinarily accessible. These works 

 also show how much more had been done by 

 the early observers than is credited to them 

 by most modern writers, partly on account of 

 facts becoming public property in course of 

 time, and partly on account of the impossi- 

 bility of doing justice to so many men at all 

 times. Yet these men were the intellectual 

 ancestors in the field of surface geology. 

 Another lesson is taught that conclusions of 

 many of the most distinguished writers have 

 not withstood deeper research, and have 

 been replaced by the views of others who in 

 turn will pass behind the curtains of time. 

 Yet the science was originated and devel- 



