CHAPTER XI. 



SURVEYING. 



To calculate areas. To find the distance from an inaccessible place. 

 To solve problems in connection with adits, shafts, lodes ol 

 a mine. Position of a shaft with regard to a lode. 



IN ordinary surveying, a Gunter's chain 66 feet long, and 

 consisting of 100 links, each tenth one of which has some 

 distinguishing mark attached, is very frequently used for 

 measuring lengths. When the number of square links in 

 a piece of ground is known, this divided by 100,000 (the 

 division being performed so easily by striking off five 

 figures from the right hand side to the left) will represent 

 the number of acres in the area. 



To find how many acres there are in a rectangular piece 

 of ground, multiply the length in links by the breadth in 

 links, and divide the result by 100,000. 



Example. Find the area in acres of a rectangular piece 

 of ground, the length of which is 1,225 links (that is, 12 

 chains and 25 links), and the breadth 150 links (that is, 

 one chain and a half). 



12 chains 25 links. 



AREA. 



Number of acres = 



FIG. 60. 



1225 x 150 



100000 

 1-83750 acres. 



