26 AGRICULTURAL ENGINEERING 



complete and clear enough to make it easy for anyone to find 

 the corners again at some future time. 



PROBLEMS FOR PRACTICE 



(In order to carry out the following problems it will be necessary 

 to be provided with equipment consisting of tapes, pins, and range 

 poles.) 



1. With chain and range poles lay off a right angle. 



Note. 3, 4, and 5 feet, or corresponding multiples of these dis- 

 tances, are sides of a right angle triangle. Give the theorem of geometry 

 upon which this is based. (Fig. 7). 



2. Measure the distance between two points a thousand feet or 

 more apart and check with the results obtained by the instructor. 



True Line 



Fig. 8. Sketch showing: method of locating points on a desired line 

 between two points not visible from each other from a random line. 



3. Let each student pace this or some other known distance and 

 determine the length of his pace. 



4. Estimate certain distances by pacing, and then measure accu- 

 rately with a steel tape. 



5. Chain over a hill between two points not visible from each 

 other. 



Range poles should be set at the points and then the chainmen 

 with range poles should take such positions on each side of the hill as 

 will enable each to see over the hill and past the other chainman to 

 the range pole beyond. The chainmen then range each other in, mak- 

 ing several trials. 



6. Chain between two points when the view is obstructed by woods 

 or other objects. 



To accomplish this, run a trial or random straight line as near as 

 possible to the distant point, leaving fixed points at known distances. 

 Upon finding the error at the terminus, correct all other points into 

 line a proportionate amount. Then the desired line may be chained. 



