362 



SCIENCE. 



[N. S. Vol. IV. No. 89. 



appearances of the objects, their points of dif- 

 ference and their resemblances. The beginner 

 ought to have the way smoothed off for him 

 and every turning in the road explained. The 

 discipline for the student should not come in 

 the labor of mastering the principles of the sci- 

 ence, but in applying them. Time is too short 

 and too valuable to require the learner to spend 

 all his time in clearing his path from the stumps, 

 stones and other rubbish the instructor has left 

 there, either from incompetence, ignorance or 

 indolence. It is this unnecessary rubbish left in 

 the way that wastes the time of our pupils and 

 causes so many of them to graduate before they 

 have really learned anything so that they can 

 apply it. 



The preface to "Williams' Manual informs the 

 reader in substance that the book is designed 

 to teach beginners to distinguish the different 

 kinds of rocks by means of the naked eye and 

 ordinary lens, and to inform engineers about 

 the various uses of rocks. 



Looking at the first object — the student's use 

 — the following sentence, culled from many, 

 will give an idea of the lucidity of expression 

 employed : "It may also be advanced that it 

 does not require a greater amount of heat to 

 metamorphose the walls in the one case than in 

 the other, and that it is as easy to suppose the 

 walls heated before the stoppage of the flow, 

 either by the length of time during which the 

 flow passed or from the fact that the whole re- 

 gion was heated to a point just below metamor- 

 phism (by orogenic or other causes) before the 

 fracture and intrusion took place, and that the 

 intrusive supplied the needed increment for 

 metamorphism " (p. 3). This doubtless was 

 one of the ' hot times ' frequently heard of, but 

 never before known to produce geological 

 metamorphism through their length. This 

 explanation will not only clear matters up 

 for the beginner, but will assist the physical 

 geologist in solving some of his most difficult 

 problems. 



How much attention could the author have 

 paid to the needs of students, when, alone of 

 all the manuals relating to the microchemistry 

 of minerals, he refers to the French one of 

 Klement (misspelled Klemert) and Renard, a 

 publication that has long been out of print, 



and so rare that the reviewer has not been able 

 to secure even a single copy after years of 

 endeavor. 



The only proper place mineralogy, as such, 

 has in a text-book of lithology is when the 

 space is devoted to pointing out the modes of 

 occurrence of the minerals in rocks and the 

 methods employed for their macroscopic iden- 

 tification. 



In this book the first is briefly done and the 

 latter hardly at all, while the chief portion de- 

 voted to mineralogy falls into the category 

 usually known as ' padding.' The part of the 

 work relating to the general definitions is its 

 most valuable portion, although the statements 

 here are deficient in clearness and precision, 

 while much unnecessary matter has been in- 

 troduced. 



In the rock descriptions what beginner could 

 macroscopically identify an obsidian by being 

 told as its definition that it was 'a compact 

 glass of varying color and luster, of a high 

 acidity, and with content of chemically com- 

 bined waters never more than one per cent.' 

 (p. 114) ? Or how is the learner to distinguish 

 amphibolite from hornblende schist when the 

 massive and schistose states occiir almost in the 

 same hand specimen, if he is guided by these 

 definitions ? ' Amphibolite, a granular aggre- 

 gate of dark green to black hornblende with 

 more or less quartz, and sometimes chlorite.' 

 ' Hornblende-schist, a granular and schistose 

 aggregate of the above minerals with similar 

 silica and specific gravity.' 



Throughout the book the descriptions and 

 definitions of the rocks are not clear and accu- 

 rate for macroscopic work, so that the beginner 

 can find any clues to lead him on through the 

 labyrinth. No directions are given to show 

 him how he may avoid errors, and the char- 

 acteristic appearances of the rocks are almost 

 unnoticed. 



It is such teaching as this, the reviewer be- 

 lieves, which crowds a student's head with a 

 mere jumble of words, but leaves him destitute 

 of any real knowledge of their application. 



Although this is the second edition, the critic 

 cannot see that the work has any use or place 

 in the class room or laboratory. He regards it 

 as one of the most worthless manuals on macro- 



