COLLECTIONS OF FACTS. 



2S5 



A geometrical pace is 4.4 feet English ; and an English 

 mile contains 1,200 paces, or 1,760 yards, or 5,280 feet. 



A Scotch mile contains 1 ,500 paces ; a German mile 

 4,000 ; a Swedish and Danish mile 5,000 ; the Russian 

 mile 750. 



A hand, used in measuring the height of horses, is 4 

 inches. 



A surveyor's chain is 4 poles, or 66 feet, divided into 

 100 links of 7.92 inches. A square chain is 16 poles, and 

 10 square chains are an acre. 640 square acres are a 

 square mile ; and 4,840 square yards are an acre, 69.58 

 yards each way. 



The Irish acre is 7,840 square yards. 



The Scotch acre is 1.27 English. 



A French arpent is f of an English acre. 



121 Irish acres are equal to 196 English. 



48 Scotch acres are equal to 61 English. 



11 Irish miles are equal to 14 English. 



80 Scotch miles are equal to 91 English. 



A sea league is 3.4536 miles, or the 20th of a degree. 

 6,078 feet are a sea mile. 



A degree at the equator is 365,101 feet, or 69.148 miles, 

 or 69if nearly. In latitude 66° 20', Maupertuis meas- 

 ured a degree of latitude, in 1737, and made it 69.403 ; 

 and Swanberg, in 1803, made it 69.292, At the equator, 

 in 1744, four astronomers made it 68.732 ; and Lambton, in 

 1803, latitude 12°, 68.743. Mudge, in England, made it 

 69.148. Cassini, in France, in 1718 and 1740, made it 

 69.12, and Biot, 68.769 ; while a recent measure in Spain, 

 makes it but 68.63, which is less than at the equator, and 

 contradicts all the others, proving the earth to be a prolate 

 spheroid, which v/as the opinion of Cassini, Bernouilli, 

 Euler, and others, while it has more generally been re- 

 garded as an oblate spheroid. 



Degrees of longitude are to each other in length, as the 

 cosines of their latitudes. For every 10° they are as fol- 

 lows : — 



Equator, 69.2 



10° 68.15 



20° 65.27 



30° 59.93 



40° 53.1 



50° 44.48 



55° 39.69 



60° 34.6 



70° 23.67 



80° 12.02 



The pendulum which vibrates seconds, 39.1393 inches 



