November 1, 1895.] 



SCIENCE. 



597 



e\'en by the mountains, colors that vie with sunsets, 

 and sounds that span the diapason from tempest to 

 tinkling raindrop, from cataract to bubbling foun- 

 tairi. But more, it is a vast district of country. 

 Were it a valley plain it would make a State. It can 

 be seen only in parts from liour to hour and from day 

 to day and from week to week and from month to 

 month. A year scarcely suffices to see it all. It has 

 infinite variety, and no part is ever duplicated. Its 

 colors, though many and complex, at any instant 

 change with the ascending and declining sun ; lights 

 and shadows appear and vanish with the passing 

 clouds, and the changing seasons mark their passage 

 in changing colors. You cannot see the Grand Can- 

 yon in one view, as if it were a changeless spectacle 

 from which a curtain might be lifted, but to see it 

 you have to toil from month to month through its 

 labyrinths. It is a region more difficult to traverse 

 than the Alps or the Himalayas, but if strength and 

 courage are sufficient for the task, by a year's toil a 

 concept of sublimity can be obtained, never again to 

 be equaled on the hither side of Paradise." 



Considered as a whole, the book is a mono- 

 graph on a region classic in geology and eth- 

 nology, and a summary history of the develop- 

 ment of science in this region. It is at the 

 same time a record, unique in its fullness, of a 

 memorable exploratory trip, the most arduous, 

 save that of Francisco Pizarro on the headwaters 

 of the Amazon, in the annals of America, and 

 one saved from the verdict of foolhardiuess 

 only by success. No geologic or ethnologic 

 library or collection of Americana will be com- 

 plete without it. As a historical treatise the 

 work might have been made more valuable by 

 setting forth the origin and development of 

 great generalizations, and tracing the growth 

 of knowledge concerning the region and its 

 various aspects, though by such treatment its 

 simplicity and unity would have been impaired. 



From preface to summary the pages teem 

 with matter-of-fact reason, mingled with poetic 

 imagery, expressed in clear and fluent lan- 

 guage. The strong personality of the author 

 can be read only between the lines of scientific 

 observation or generalization, or of the narra- 

 tive of patient and persevering mastery of na- 

 tural forces in the canyon. Reading between 

 the lines, the philosophy of the author may be 

 recognized in its practical application. He ex- 

 plored the canyon to the end that knowledge 



might be gained ; he trained collaborators in 

 geology and ethnology, giving them freely of his 

 acute observations and profound generaliza- 

 tions, to the end that knowledge might be dif- 

 fused ; he would have it that the book should 

 be a monument to his companions in the ex- 

 ploration, including those who faltered at the 

 eleventh hour ; and self is lost in the immor- 

 tality of knowledge useful to mankind. 



The publishers have done their part well. 

 The print is large and clear and carefully proof- 

 read ; the paper is good, and the illustrations 

 are ample and well selected. Nearly all of the 

 illustrations have been used before, either in 

 governmental publications or in magazines, and 

 to some readers this fact may convey a bad im- 

 pression ; but all of the illustrations have grown 

 out of the work of the author. In some cases, 

 too, it might have been desirable to connect the 

 illustrations more closely with the text by 

 legend or otherwise, and this was perhaps 

 avoided only through desire to economize space. 

 The cloth binding is good, and the binding in 

 leather is excellent. W J McGee. 



Petrology for Students. An introduction to the 

 study of Rocks under the Microscope. By 

 Alfeed Haekbr. Published by Maemillan 

 & Co., New York. 1895. Price, $2.00. 

 As the author states in the preface, this text- 

 book is prepared especially for English students, 

 nevertheless, it will be found very useful for 

 those beginning the study of petrographj"- in 

 this countiy who wish a text-book written in 

 English. No systematic account of the crys- 

 tallographic and optical properties of minerals 

 has been attempted, and for such information 

 the student is referred to the translation of 

 Professor Rosenbusch's volume on the rock- 

 making minerals. But as an introduction to 

 the study of the rocks themselves a number of 

 useful observations of a general nature are pre- 

 sented upon the characters of minerals in this 

 section, and especially the latest methods of 

 distinguishing the different varieties of feldspar. 

 In treating so complex a subject as the optical 

 properties of minerals in thin sections in such 

 a condensed manner it is doubtful whether the 

 author can meet the wants of a beginner. It 



