CHAPTER II 



MEASURING; USE AND CARE OF INSTRUMENTS 



Instruments for Measuring Distances. Often students 

 are led to think that it is impossible to make a survey without 

 a very elaborate equipment of expensive instruments, but 

 this is not true. An agricultural survey, such as is usually 

 required by the farm owner or manager, can be accomplished 

 with simple and quite inexpensive instruments. Where the 

 boundary of the tract of land is known, a practical survey 

 may be made with a surveyor's chain or tape. 



Gunter's Chain. Much of the land in the United States 

 was surveyed originally with the Gunter's chain, which is 

 now but little used. This chain is 66 feet 

 long, divided into 100 links, each of which, 

 including the connecting rings at the ends, 

 is 7.92 inches long. The links are made of 

 steel or iron wire, and the better chains 

 have the open joints soldered or brazed to- 

 gether. The reason for making the Gunter's 

 chain of the length of 66 feet or 100 links is 

 owing to its convenient relation to the stand- 

 ard units of length and area in use. The 

 chain is 1-80 of a mile, or four rods. A 

 square chain is 1-10 of an acre. Thus ten square chains 

 make an acre, and this, together with the fact that links 

 may be written as a decimal of a chain, greatly facilitates 

 computations. To illustrate, 1625 square chains equal 162.5 

 acres, and 15 chains and 24 links equal 15.24 chains. 



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folded. 



