MEASUREMENTS 9 



persons employed in certain occupations recognize only the 

 special units, and unless measurements are given in such 

 units do not readily interpret them. In land measurements 

 the United States Land Office recognizes the use of the 

 chain as the standard, with the link as the subdivision. 

 The chain is referred to in several ways, as Gunter's chain, 

 surveyors' chain, four-rod chain, four-pole chain, and 

 four-perch chain. A link is one-hundredth part of the 

 chain. The equivalent of the chain is 66 feet; of the link, 

 7.92 inches. 



Rod. The common term for expressing land lineal units 

 on the farm is the rod, which is one-fourth of a chain, or ib}4 

 feet. The terms perch and pole are used to refer to the same 

 unit. The terms "pole" and "rod" probably originated 

 from the use of a slender piece of wood cut to the required 

 length and used for the measurement of land. 



Mile. The common term for expressing distances of travel 

 is the mile, which is equivalent to 80 chains or 320 rods or 

 5,280 feet, a quarter-mile being 20 chains, 80 rods, or 1,320 

 feet. 



Engineers' chain. Civil engineers in all classes of work 

 except land surveys use the engineers' chain, a chain 100 feet 

 long subdivided into feet and decimals of a foot. It is cus- 

 tomary, even in measuring land, to use the 100-foot chain 

 and then reduce the measurements and record them in 

 terms of the surveyors' chain, thus avoiding two units of 

 measurement. Care should be exercised, in the discussion 

 of land measurements, not to confuse the 66-foot chain with 

 the 100-foot chain used in other engineering. In land sur- 

 veys the chain is always 66 feet. 



Station. The term station is used to indicate one length 

 of a unit of measurement as marked on the ground by stakes. 

 It is not necessarily a fixed unit. Unless otherwise qualified, 

 it may be considered as 100 feet in length. The station 

 number is indicated on the stake which marks the far end 

 of the station from the starting point. When the stake 



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