August 2, 1906] 



NA TURE 



315 



in water, and that hence dolomite-masses are capable 

 <if givinjj rise to typical karst-phenomena. It is 

 <ibscrved (p. 195) that the air of caves is a remarkable 

 conductor of electricity. The relation of typical karst- 

 surfaces to the removal of forests is pointed out, and 

 French areas, cleared after the Revolution, are cited 

 as examples. The French causscs, by-the bye, deserve 

 rather longer mention, considering how accessible they 

 now are from Millau, and how finely they illustrate 

 the author's thesis. But we welcome the use made 

 of the " dolinas " and " poljes," names that recall the 

 fascination of the Slavonic east. The author's classi- 

 ficatory instinct introduces us also to marine erosion 

 and to Fingal's Cave; to a glimpse of the fauna of 

 caves; and to caves as the haunt of early man. But 

 it is the treatment of the karst-phenomena that will 

 probably give this book a place among works of 

 reference, although precise references to original 

 papers are rare in it, and although it has, strange to 

 say, no index. G. A. J. C. 



OVR BOOK SHELF. 



The Outlook to Nature. By L. H. Bailey. Pp. ix + 



296. (New York : The Macniillan Company ; 



London: Macmillan and Co., Ltd., 1905.) Price 



55. net. 

 Prof. Bailey is well known as one of the most fertile 

 and inspiring of teachers of science as applied to 

 agriculture and particularly to horticulture, who has 

 built up a great school at Cornell and has also been 

 the source of a wave of teaching from nature among 

 the schools of the United States. 



In all Prof. Bailey's work may be seen the qualities 

 of the enthusiast, who is moved, and gets his power 

 tu move his followers, by considerations other than 

 those which are the ostensible object of his work. 

 The life of the country-side, farming and gardening, 

 then, are to Prof. Bailey something more than a 

 scientific study or a means of earning a livelihood — 

 they are the great regenerating influences of modern 

 life. He sees civilised existence getting every dav 

 more complex, more nois)', more hurried, more exact- 

 ing; nor in the interests of efficiency does he expect 

 or desire any wholesale return to a more primitive 

 mode of living. But what he does plead for is the 

 *' return to nature " in " our personal and private 

 hours " as a " means of restoring the proper balance 

 and proportion in our lives." The book consists of 

 four lectures, delivered in Boston, on such topics as 

 the relation of country to city, the part that nature- 

 teaching should play in school life and the organ- 

 isation of rural teaching generally, with a final essav 

 on the position of evolutionary conceptions with re- 

 gard to religion. 



We get a vivid and interesting presentment of the 

 ■opinions and convictions which have made Prof. Bailey 

 a living force in .\merican education ; we see that 

 the writer is a passionate lover of nature with a 

 strain of the poet in him, but we do not alwavs find 

 his treatment convincing. The book must be judged 

 as literature, and in literature neither the best of inten- 

 tions nor the finest of emotions count unless you ran 

 express them with something of the freshness and 

 inevitability of a living thing; here we often find 

 the thoughts and arguments of Thoreau, but without 

 his clear-cut and startling intensitv of expression. 

 Prof. Bailey is rhetorical, and that means he is some- 



NO. 1 91 8, \^OL. 74] 



times more concerned with the decorative value of his 

 periods than with their absolute truth ; for instance, 

 he makes a point that we go to a gallery to see a 

 picture of a sunrise when we might see the sunrise 

 itself! forgetting that it is only the awakened eyes 

 which can see at all. " I never see a sunset like that," 

 objected the critic to Turner; "Don't you wish you 

 could," answered the artist. 



However, putting aside the question of these " airs 

 and graces," Prof. Bailey's thesis is sound enough; 

 civilisation is dying and will die of its own self- 

 produced poisons ; it is only by the improbus labor 

 on the land that ihe human race seems able to 

 persist. A. D. H. 



Lecture Notes on Chemistry for Dental Students. By 

 Dr. H. Carlton Smith. Pp. viii-(-273. (New York : 

 John Wiley and Sons; London : Chapman and Hall, 

 Ltd., 1906.) Price 10s. 6d. net. 

 The connection between dentistry and chemistry is 

 a two-fold one. The practical dental surgeon is a 

 worker in metals ; he has to prepare amalgams for 

 stoppings and carry out a multitude of similar oper- 

 ations ; hence his need for a knowledge of inorganic 

 chemistry. No less important is the second link; he 

 must know the composition of the teeth, the action 

 upon them of the reagents and drugs he employs ; he 

 must understand the action of ferments, whether they 

 are contained within the micro-organisms of the 

 mouth or in the secretions, like saliva, which come 

 in contact with the teeth; hence his need for a know- 

 ledge of organic, and especially of physiological, 

 chemistry. Dr. Smith has produced a work which 

 supplies such needs, and one is glad to see he has 

 provided an over-supply; for instance, the sections on 

 physiological chemistry do not deal exclusively with 

 saliva, though naturally this subject is treated with 

 special fulness. Tliis is as it should be ; the less 

 specialised and narrow a dentist's education, the 

 more is he likely to benefit those under his care. 



In the analyses given of the different parts of the 

 teeth. Dr. Smith states that enamel contains 3 per 

 cent, of organic matter. He does not allude to the 

 work of Tomes, in which it was shown that enamel 

 contains no organic matter ^at all, and what was 

 formerly given as organic matter (bv difference) is 

 really due to water. It is not a very important point, 

 and possibly the author was not aware of Tomes's 

 research on the question. 



.4 Study of the Sky. B\- Prof. Herbert A. Howe. 



Pp. xii-l-340. (London : Macmillan and Co., Ltd., 



1906.) Price 2S. 6d. 



This is a cheap edition of a book that appeared 



onginally several years ago. Written in attractive, 



simple language. Prof. Howe's volume is just the 



work for those readers who, knowing little or nothing 



1 of the oldest of sciences, wish to become personally 



i acquainted with the wonders of the skv. 



A very pleasing feature of this book is the way in 



which the reader is forced to observe and experiment 



I for himself. Chapter i. gives a brief historical sketch 



of astronomy, and is followed by five chapters dealing 



1 with the constellations observable at various seasons, 



t and their apparent diurnal and annual motions. Then 



1 come three chapters dealing with astronomers in 



I general and particular, and their tools. A chapter on 



time and the method of keeping it is followed bv five 



(xi.-xv.) chapters dealing seriatim with the members 



of the solar system. The concluding chapters discuss 



in a simple but instructive fashion comets and meteors, 



I the fixed stars, and the nebulae. 



