790 



THE STANDARD DICTIONARY OF FACTS 



out of the ship while sailing, as soon as it touches 

 the water it ceases to partake of the ship's mo- 

 tion, so that the ship goes on and leaves it be- 

 hind, while the line is unwound from the reel, 

 so that the length of line unwound in a given 

 time gives the rate of the ship's sailing. This 

 is calculated by knots made on the line at cer- 

 tain distances, while the time is measured by a 

 sandglass running a certain number of seconds. 

 The length between the knots is so proportioned 

 to the time of the glass that the number of knots 

 unwound while the glass runs down shows the 

 number of nautical miles the ship is sailing per 

 hour. Thus, if the glass be a half-minute one, 

 it will run down 120 times in an hour. Now. 

 since a nautical mile contains about 6,076 feet, 

 the 120th part of this is about 50$ feet; so that 

 if the spaces between the knots be 50$ feet, the 

 number of knots and parts of a knot unwound 

 from the reel in half a minute is the number of 

 miles and parts of a mile the ship runs in one hour. 

 Mortality. In an extended sense, the con- 

 dition of all organized bodies of being subject 

 to the cessation of life. In the sense in which 

 it is most frequently employed, the death rate, 

 i. e., the proportional quantity of individuals 

 who, in a certain population, die in a given time. 

 If we assume the population of the earth to be 

 one thousand millions, and a generation to last 

 thirty-three years; in that space of time, the 

 one thousand millions must all die, and, conse- 

 quently, the number of deaths will be, by ap- 

 proximation : 



Each year, 30,000,000 



Each day, 82,107 



Each hour, 3,421 



Each second, .... 1 nearly. 



One-quarter of the population die at or before 

 the age of 7 ; the half part of it die at or before 

 the age of 17. One in 100,000 persons reaches 

 the age of 100 years; one in '500 reaches the age 

 of 90; one in 100, the age of 60. 



DEATH RATES FROM CERTAIN CAUSES IN 



THE UNITED STATES 



(From the latest statistics.) 



1 Including general tuberculosis. 2 Including pericar- 

 ditis. 3 Including cholera morbus, colitis diarrhoea, 

 dysentery, and enteritis. 4 Including Bright's disease. 



