NATURAL DEATH, PUBLIC HEALTH 251 



in a different country. The heavy solid portion of each 

 curve shows the region for which census data exist. The 

 lighter broken part of the curve shows the portions out- 

 side this observed range. The circles show the *actual, 

 known observations. The first curve deals with the popu- 



FRANCE. 



t. IS 

 % 



P 



i: 



J 



7 



/ 



i:±: 



nil 



MOO !o 49 eo eo noo io *o 60 ao ^ooeo to eo eo ooo 90 to so eo zooo 



YCAes 

 Fig. 62. — Showing the curve of growth of the population of France. 



lation of the United States. Here the observations come 

 from the first part of the curve, when the population was 

 leaving the lower asymptote. First should be noted the 

 extraordinary accuracy with which the mathematical 

 theory describes the known facts. It would be extremely 

 difficult, by any process, to draw a curve through the ob- 

 served circles and come nearer to hitting them all than 

 this one does. 



Before considering the detailed consequences of this 

 United States curve in relation to the whole population 

 history of the country, let us first examine some curves 

 for other countries, where the observed data fell in quite 

 different portions of the "population orbit." Figure 62 



