448 



THE SCIENTIFIC MONTHLY 











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BRESLAU 



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LIFE. 



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5 10 15 ZO Z5 SO 55 OO *5 50 55 60 65 



75 SO 85 SO 35 IO0 



YEABS OF LIFE 

 FIG 2 COMPARING THE EXPECTATION OF LIFE IN THE 17TH CENTURY WITH THAT 

 OF THE PRESENT TIME 



the end of the seventeenth century. From this diagram it appears that 

 at birth the expectation of life of an individual born in Breslau in the 

 seventeenth century was very much lower than that of an individual 

 born in the United States in 1910. The difference amounts to approxi- 

 mately 18 years! At 10 years of age, however, this difference in ex- 

 pectation of life had been reduced to just over 12 years; at age 20, to 

 a little less than 10 years; at age 30 to 7-1/3 years; at age 50 to just over 

 4 years; at age 70 to 1-1/2 years. At age 80 the lines have crossed. 

 The individual 80 years old in Breslau could expect to live on the aver- 

 age a half year longer than the individual of the same age in the United 

 States in 1910. At age 83, the last year covered by Halley's table, the 

 17th century individual could expect on the average to live approxi- 

 mately a year and a half longer than his twentieth century brother. 

 So then what the diagram shows is that the expectation of life at early 

 ages was vastly inferior in the seventeenth century to what it is now, 

 while at advanced ages the chances of living were distinctly better — 

 relatively enormously better — then than they are now. Let us defer 

 the further discussion of the meaning and explanation of this curious 

 fact until we have examined some further data. 



Figure 3 compares the expectation of life in England at the middle 

 of the eighteenth century, or about a century later than the last, with 

 present conditions in the United States. Again we see that the expecta- 

 tion at birth was greatly inferior then to what it is now, but the differ- 

 ence is not so great as it was a century earlier, amounting to but 12-3/4 

 years instead of the 18 we found before. Further it is seen that, just 

 as before, the expectations come closer together with advancing age. 

 By the time age 45 — middle life — is reached the expectation of life was 

 substantially the same in the eighteenth century as it is now. At age 

 47 the eighteenth century line crosses that for the twentieth century, 



