12 ENGINEERING ON THE FARM 



One of the errors in pacing is caused by losing count of the 

 strides taken. The number of paces carried in the mind 

 usually should not exceed ioo. When the count reaches 

 ioo, record should be made in a notebook or by means of 

 placing some small object in an empty pocket. The fingers 

 may be used if a finger on the right hand is closed each time 

 one hundred paces are covered. When all the fingers on the 

 right hand are closed, it indicates that five hundred paces 

 have been counted. One finger on the left hand can then be 

 closed and all on the right hand opened up. In this manner 

 the left hand is tallying five hundred paces, the right hand one 

 hundred paces, and the mind the individual pace. The only 

 objection to this method is the danger of straightening the 

 fingers when one is spoken to or stumbles on rough ground. 



Wheel revolutions. Wheel revolutions on level ground 

 give more correct results than pacing. An ordinary buggy 

 or wagon wheel can be used if one of the spokes is marked 

 with a piece of cloth near the rim. The number of revolu- 

 tions of the wheel between the given points multiplied by the 

 distance around the tire of the wheel gives the required 

 measurement. The tendency of the wheel to slide going 

 up and down hill decreases the accuracy of this method. 

 Bicycles and automobiles are usually provided with measur- 

 ing devices of this type. There is a mechanical arrangement 

 that measures the number of revolutions, and the exact 

 distance passed over can be read from a dial. A similar 

 device can be purchased for use on a buggy or other wheel 

 vehicle. If such a device is used, care should be taken to 

 adjust the instrument to the circumference of the wheel. A 

 device that would give accurate results on a wheel o feet in 

 circumference would not give accurate results on a 10-foot 

 wheel. If a recording device is to be changed frequently 

 from one vehicle to another, it is better to purchase one that 

 records revolutions and not direct distances, as the distance 

 may be computed by multiplication of the number of revolu- 

 tions by the circumference of the wheel. 



