326 



THE POPULAR SCIENCE MONTHLY. 



number of female births, as compared with the number of male births, 

 increases as the birth-rate increases. 



At the Cape of Good Hope the Boers are very prolific — six or seven 

 is a small family, and from twelve to twenty children are not unusual ; 

 while the badly nourished and overworked Hottentots seldom have 

 more than three children, and many of the women are barren, and 

 Quetelet says that in 1813-'20 the free whites gave birth to 6,604 boys 

 and 6,789 girls, or 97'2 boys to every 100 girls ; while during the same 

 time the Hottentot slaves produced 2,936 boys and 2,826 girls, or 103-9 

 boys to each 100 girls. 



The birth-rate is higher in towns than in the country, and more 

 boys are born for each hundred girls in the country than in the towns. 



Thus, in Prussia, in 1881, the number of boy-births for each 100 

 girls was 106'36. 



In Berlin it was 105*70 



In large towns it was 105*72 



In middle towns it was 105 "44 



In small towns it was 106 14 



In the country it was 106"62 



This table shows that in all the towns the ratio of boys was below 

 the average for the whole of Prussia, and that in Berlin it was very 

 much below the average. 



Ploss was the first to point out that there is an excess of female 

 births in time of prosperity, and he found that in Saxony the ratio of 

 boy-births rose and fell with the price of food, and that the variation 

 was most marked in the country. 



It is well known that the number of conceptions among mankind 

 is greater at some seasons of the year than at others, and from a 

 record of nearly 10,000,000 births During has compiled the follow- 

 ing table, which shows that the ratio of boy-births is greatest in three 

 months when the birth-rate is smallest : 



