132 



POPULAR SCIENCE MONTHLY. 



From some pai=sa{res in their writings it 

 would seem that each of these worthies came 

 within a step or two of discovering all the 

 main facts relating to the composition of the 

 air, but each failed to look quite far enough 

 in the right direction. Boyle, it appears, rea- 

 soned shrewdly from imperfect observations ; 

 Mayow died young ; while Hales accumulated 

 many and definite experimental facts, but 

 lacked the ability to make use of them. All 

 were hampered by the current errors of their 

 time, among which the chief were the inabil- 

 ity to distinguish one gas from another, lack 

 of attention to gain or loss of weight, and 

 above all erroneous ideas regarding combus- 

 tion. Prof. Ramsay shows how the phlo- 

 gistic theory, which came up about the end 

 of Boyle's life, interfered with the researches 

 of his successors Black, Rutherford, Priest- 

 ley, and Cavendish until it was overthrown 

 by Lavoisier. We are told something about 

 the achievements of each of these men, 

 and the account is made more interesting by 

 including descriptions and portraits of the 

 men themselves. After Cavendish little ap- 

 parently remained to be done but to make 

 more exact determinations of the constitu- 

 ents that had been found in the air. But in 

 the course of some investigations in 1892 

 Lord Ray leigh noticed that nitrogen prepared 

 from ammonia is somewhat lighter than at- 

 mospheiic nitrogen. A i-esearch undertaken 

 to find the reason for this difference brought 

 out the existence of the inert argon. The 

 circumstances of the discovery and the rea- 

 soning which led to it are set forth by Prof. 

 Ramsay, who adds chapters giving the prop- 

 erties of argon and its po.-ition among the 

 elements. The author has succeeded well in 

 keeping his book within the comprehension 

 of the persons without special scientific train- 

 ing for whom it was written. 



Prof. Crockett's Elements of Plane and 

 Spherical Trigonometry* by a mathemati- 

 cian of note who is Professor of Mathemat- 

 ics and Astronomy in the Rensselaer Poly- 

 technic Institute, has been prepared for the 

 use of beginners in the study. Assuming 

 that a high degree of proficiency can not be 

 expected from such students, the author, not 



* Elements of Plane and Spherical Trigonome- 

 try, with Tables. By C. W. Crockett. American 

 Book Company. Pp. .^11. Price, $1.25. 



striving after original demonstrations, has 

 limited himself to the selection of simple 

 proofs of the formulas, to which geometrical 

 proofs have in many cases been added. The 

 definitions and explanations are admirably 

 clear and concise. The numerical examples 

 have been computed by the author, with spe- 

 cial attention to correctness in the last deci- 

 mal place. The tables are a special feature, 

 are printed from differentiated type, and on 

 paper of a different tint from the text, so as 

 to make them easier to turn to. They give 

 five places, while the angles in the examples 

 are given to the nearest tenth of a minute. 

 We find the book lucid and convenient. 



The recent book of Prof. Keasbey * on the 

 Nicaragua Canal urges frankly and emphatic- 

 ally the choice of the Nicaragua route for a 

 canal across Central America, and the assump- 

 tion by the United States of a dominant posi- 

 tion in the political control of this water way. 

 The author opens his discussion with a brief 

 description and comparison of the ten or 

 twelve more or less distinct routes that have 

 been proposed, expressing the decided con- 

 viction that the Nicaragua and Panama routes 

 are the only two worth considering, with the 

 advantage on the side of the former. The 

 greater part of the volume is devoted to a 

 history of the attempts that have been made 

 to construct canals in this region and to ob- 

 tain political control of the territory through 

 which they would pass. The record begins 

 with the first Spanish explorations, and men- 

 tions canal projects of Spanish engineers 

 formed before 1550. A chapter on the Eng- 

 lish freebooters opens an account of the 

 struggle between England and Spain, lasting 

 into the early part of the present century. 

 The term from 1815 to 1865 Prof. Keasbey 

 characterizes as a period of private initiative 

 in canal projects. Two events in this divi- 

 sion of his record which have an important 

 bearing on the idea of cutting the American 

 isthmus are the enunciation of the Monroe 

 doctrine and the execution of the Clayton- 

 Bulwer treaty. The time since 1865 he de- 

 scribes as a period of governmental activity 

 in this matter, and he closes his chronicle of 

 recent events by givmg his view of the po- 



* The Nicaragua Canal and the Monroe Doc- 

 trine. By Liudley Miller Keasbey. New York: 

 G. P. Putnam's Sons. Pp. 622, Svo. Price, $3.50. 



