120 



SCIENCE 



[N. S. Vol. LIII. No. 1362 



merely by opening the throttle, as in the case 

 of an automobile. 



1 Professor Bedell's book shows an tmusual 

 gift for clean cut analysis and exposition; 

 there are but few scientific or technical hooks 

 that demonstrate these qualities in so high a 



! The 'book does not attempt to extend the 

 science of aeronautics. It is devoted primarily 

 to a discussion of the problem of sustentation; 

 the matter of stability is also treated, but in a 

 qualitative way. It falls in a category between 

 the popular book, superficial and inadequate, 

 and the treatise, involved, and complicated. 

 It is a book destined for a long and useful life. 

 Lionel S. Marks 

 Harvard University 



SPECIAL ARTICLES 



A FURTHER NOTE ON WAR AND POPULATION' 



: In a note published last summer- I drew at- 

 tention to the course of the ratio 

 100 Deaths 



Births 

 in the principal belligerent countries of Eu- 

 rope between 1913 and 1918. All of the curves 

 presented, with the single exception of that for 

 Prussia, ended on a high point in 1918. The 

 question was raised as to what would be their 

 course after that year, and it was shown that 

 England and Wales gave a value of 73 per cent, 

 for 1919 against 92 per cent, for the high point 

 in 1918. The first three quarters of the year 

 1920 give for England and Wales a value of 

 46.8 per cent. This is 10 points lower than the 

 figure for 1913 ! For every death England had 

 more than two births. 



The Journal Ojficiel has recently published 

 the 1919 figures for France (77 non-invaded 

 departments only) to the following effect : 



100 Z> 



63569400 



-^ = 154 per cent. 



B 413379 



This figure compares (for the same territory) 



1 Papers from the Department of Biometry and 

 Vital Statistics, school of hygiene and public 

 health, Johns Hopkins University, No. 27. 



2 Pearl, E., Science, N. S., Vol. LI., pp. 553- 

 596, 1920. 



with 198 in 1918, 179 in 1917, 193 in 1916, 169 

 in 1915, 110 in 1914, and 97 in 1913. In other 

 words, in the next year immediately following 

 the cessation of hostilities France's death-birth 

 ratio came back to less than that of 1915, the 

 first whole year of the war. With an increase 

 of 157 per cent, in marriages in 1919 over 1918 

 there seems little risk in predicting that 1920 

 will show a ratio not far from 100, which will 

 be about the normal prewar status, France 

 having had for some time a nearly stationary 

 population. The 1920 vital index for France 

 may well prove to be considerably below 100. 

 Another, and even more striking illustra- 

 tion of the exceedingly transitory effect of war 

 upon the rate of population growth, is seen in 

 the figures for the City of Vienna. Probably 

 no large city suffered so severely from the war 

 as did this capital. Yet observe what has 

 happened, as set forth in Table I. To this 

 table I have added, for the sake of rounding 

 out the data of this and the former paper, the 

 death-birth ratios of the United States Kegis- 

 tration Area for as many years as they are 

 available, and for England and Wales, 1912 to 

 1920 (first three quarters of latter year). 



TABLE I 



Percentage of Deaths to Births 



These figures are shown graphically in Fig- 

 ure 1. 



We note that : 



1. The high point of the Vienna curve in 

 1918, 229 per cent., is higher than that for 

 France (198 per cent.), and probably higher 

 than for any other equally large aggregate of 

 population in the world. 



3 First three quarters of year only. 



