28 



ASTRONOMICAL and 



y 



factors are northings and weflings, or fouthings and eaftings, 

 into anotlier fum. To aflifl the memory let the annexed dia- 

 gram reprefent the cardinal points ; and let it N 



be conceived, that the producfls, to be brought 



into one fum, have their factors in the order \V ^1 -E 



N E, S W ; and that thofe, to be brought into 

 the other fum, have their facftors in the con- g 



trary order N W, S E. Laftl J- take the difference of thefe fums ; 

 ^-j^ of which will be the required area of the field. 



EXAMPLE I. 



C> S. B. 



1981 



U74 



S. 4^^ W. 6 



4 07 



4.40 



N.64^E. II 

 10 78 



\ 



9-67 

 14.94 



Svippofe the furvey of a field to be as 



follows : prom the firfl boundary S. 69 



43' W. 21.12 chains : thence N. 55° E. 18 

 chains : thence 8.42° W. 6 chains : thence 

 N. 64° E. 12 chains : thence S. 24" W. to 

 the firfl boundary. Tlie required area 

 is 47.0065 chains, or 4*70065 acre; 



s.34^ W.417 



f 10 



.3.81 



7-3 a 



■^5 5i «i Ji 



NE.S W. )NW.SE. 



44.1200 

 104.2426 



148.4626 

 54-4496 



$40130 

 47'0^6i 



3W286 

 18.5210 



54.4496 



"When the fum of the eaftings is equal 

 to the fum of the weftlngs, and the fum 

 of the northings is equal to the fum 

 of the fouthings ; which is known by the 



ultimate 



diftance of the laft 





fide being equal to the perpendicular of 

 the fir ft fide, but 



of 



different name 



the furvey is rightly taken ; otherwife there is an error eith 

 in the courfes* or fides. 



In 



