Apeil 1, 1910] 



SCIENCE 



507 



ness of the theory and its value as a working 

 hypothesis, he is unwilling to admit his 

 former error and to give to true scientific 

 workers the credit which justly belongs to 

 them. 



This obvious attempt at consistency on 

 Professor Lowell's part is rather belated, for, 

 as a rule, inconsistencies do not bother him. 

 His books are full of them. He is so inter- 

 ested in marshaling his facts and proving the 

 point at immediate issue, that he appears to 

 forget that at some other time, in some other 

 place, he has arrayed the same facts differ- 

 ently and by them proved the exact opposite. 

 In order to prove, for example, that certain 

 dark lines, which appear in his drawings of 

 Venus, really exist and form permanent mark- 

 ings on this planet, Lowell argues, against the 

 evidence of other investigators, that Venus is 

 surrounded by a very thin atmosphere, 

 " gauze of the most attenuated character " — 

 that the brilliancy of the planet is due to this 

 very thinness of atmosphere. In another 

 chapter Lowell finds the brilliancy of Jupiter 

 and Saturn mostly due to dense cloud forms 

 in their atmospheres. On the one hand, Venus 

 has no clouds because she is bright, while 

 on the other hand, Jupiter and Saturn are 

 bright because of clouds. Again these same 

 markings, or pseudo-markings, on the disc of 

 Venus have been variously described by Lowell 

 in his different papers and books. 



The book contains many loose statements of 

 scientific facts and principles, and conclu- 

 sions are drawn by special pleadings and by 

 apt illustrations rather than by any course of 

 logical reasoning. Yet with all this, and in 

 spite of exaggerations and obvious attempts 

 to create popular excitement, the book gives 

 the general reader, in an attractive form, a 

 more or less accurate conception of the latest 

 ideas in regard to the evolution of our world. 

 It is a pity that the work of such a brilliant 

 vsT-iter should be marred by his all too evident 

 faults. 



Ohas. Lane Poor 



Aerial Navigation of To-day; a Popular Ac- 

 count of the Evolution of Aeronautics. By 



Charles C. Turner. Philadelphia, J. B. 

 Lippincott Co. 1910. 8vo, pp. 327. Illus- 

 trated. 



This book, which is one of the few of its 

 kind in the English language, was brought 

 out simultaneously last autumn in this coun- 

 try and in England. Its English author 

 shows his predilection in ways hereafter men- 

 tioned, but, while he has made some long bal- 

 loon voyages he modestly refrains from ob- 

 truding them upon the reader, unlike most 

 writers of books upon aeronautics, who usually 

 emphasize the particular subject with which 

 they are most familiar. The reviewer himself 

 is no exception, since in his " Conquest of the 

 Air," a smaller contemporary work, of similar 

 scope to the one under consideration, he gives 

 first place to his own explorations in the ele- 

 ment that man has conquered after so long a 

 struggle. Mr. Turner begins with a history 

 of ballooning and the principles involved in 

 both spherical and dirigible balloons, mechan- 

 ical flight being treated in the same way. 

 There follows a chapter on the aerial ocean, 

 which is a compilation of observations by 

 European aerologists, often without context or 

 suflScient explanation. The remaining chap- 

 ters discuss the applications of aerial naviga- 

 tion and its possibilities, especially in warfare. 

 Eather out of place is the concluding chapter 

 on typical flying machines and dirigible bal- 

 loons. " Useful tables," a useless glossary of 

 English and French aeronautical terms and a 

 very inadequate bibliography occupy the re- 

 mainder of the 321 pages. The book is clearly 

 written, profusely illustrated with pictures 

 and diagrams and gives a good idea of the 

 past history and present status of aeronautics. 

 The sanguine prophecies of its future devel- 

 opment recall the extravagant and unrealized 

 hopes which were indulged in when the bal- 

 loon was invented and render the adage, 

 " never prophesy unless you know," a particu- 

 larly safe one to follow as regards this new 

 art. ' 



No book of the kind can be entirely free 

 from mistakes, but it would seem that the 

 editor of Aeronautics, who read the MS. and, 

 to quote the author, " than whom there is no 



