December 11, 1896.] 



SCIENCE. 



881 



a true man, was sent to the scaffold by the 

 Parisian mob, led by bigoted ' liberals ' and 

 atheists, with the sneer that the Republic had 

 no need of savants. As to Priestley, who had 

 devoted his life to science and to every good 

 work among his fellow men, the Birmingham 

 mob, favored by the Anglican clergymen 

 who harangued them as 'fellow-churchmen,' 

 wrecked his house, destroyed his library, 

 philosophical instruments, and papers contain- 

 ing the results of long years of scientific re- 

 search, drove him into exile, and would have 

 murdered him if they could have laid their 

 hands upon him." 



With this quotation our notice of Dr. White's 

 scholarly and fruitful work may appropriately 

 come to a close. Let us only add that the first 

 martyr to truth was the victim of a mob who 

 hated to hear his teaching. The martyrdom of 

 Socrates occurred four hundred years before 

 the appearance of that unique personality who 

 is the central figure of the dogmatic theology 

 of Christendom. 



j. g. schurman. 



Cornell University. 



Navigation and Nautical Astronomy. By F. C. 

 Stebbing, M. a.. Chaplain and Naval In- 

 structor, R. N. Macmillan & Co., London 

 and New York. 1896. 1 vol., 8vo, 328 pp. 

 Price, $2.75. 



This volume contains a complete course in all 

 the necessary subjects of modern navigation. 

 It may be recommended to those who have to 

 acquire a knowledge of the theory and practice 

 of the calculations that are required in the nav- 

 igation of ships. By incorporating the neces- 

 sary part of the Nautical Almanac for 1895 and 

 referring the examples which are to be worked 

 out to the data there tabulated, the author has 

 overcome, in an original and effective manner, 

 one of the chief obstacles which students of as- 

 tronomical navigation universally experience in 

 gaining a knowledge of the intelligent use of 

 the data contained in the Almanac. 



The book is also to be commended for the 

 large number of useful examples and problems 

 which accompany each division of the subject. 

 Where necessary, the methods are modern- 

 ized so as to treat, for change of geographical 



position during the period of observation, the 

 observations that may be made on board the 

 swift moving vessels of the present day. 



It has probably been overlooked that the di- 

 rections given on page 54 for measuring the 

 distance between two points on a Mercator 

 chart will not generally apply. ' ' The distance 

 is found (nearly) by transferring the interval 

 between the two positions to the graduated 

 meridian, as nearly as possible opposite to the 

 positions, i. e., as much below the more southern 

 as above the more northern ; this space turned 

 into minutes is the distance required." This 

 method fails in most cases in which the line to 

 be measured lies far from the middle of the chart, 

 because when the interval is transferred to the 

 graduated meridian one end or the other is 

 likely to fall outside of the border. 



Mention is not made of the generally appli- 

 cable method of taking a small number of divi- 

 sions of the graduated meridian, near the mid- 

 dle latitude of the line to be measured, between 

 the points of a pair of dividers, and stepping 

 this interval along the line to be measured. 



In definition No. 8 it is stated that "A nauti- 

 cal mile is equal to the mean length of a minute 

 of latitude, and is reckoned as 6080 feet." The 

 actual mean length of a minute of latitude of 

 the terrestrial spheroid computed upon the ele- 

 ments of the spheroid assigned by Bessel is 

 6076.23 feet, and upon the later and more per- 

 fect values assigned by Clarke, 6076.82 feet. 

 The length of the nautical mile, or Admiralty 

 knot, which is 6080 feet, corresponds more 

 nearly to one-sixtieth part of the length of a de- 

 gree of a great circle of a sphere whose surface 

 is equal in area to the surface of the earth. This 

 length is 6080.27 feet. 



G. W. LiTTLEHALES. 



A-Birding on a Bronco. By Florence A. Mer- 

 RIAM. Houghton Mifflin & Co., Boston and 

 New York. 16°, illustrated. Price, $1.25. 

 This volume is the result of the studies of two 

 seasons in southern California. About sixty 

 species of birds are spoken of, and with many 

 we become quite well acquainted as we watch 

 their nesting ways through the eyes of the sym- 

 pathetic bird lover. It has also the novel fea- 

 ture of studying birds, not only with an opera 



