THE WEIGHING OF MARKET HAY. 



27 



should be tested frequently and balanced daily, or even oftener, if 

 weather or other conditions make more frequent balancings necessary. 

 At some warehouses scales are so placed that the car remains upon 

 them while it is being loaded or unloaded ; at others they are placed 

 so that cars are moved over them when being switched to and from 

 the warehouse. . There is no material difference as to which location 

 is used, but care must be taken to see that the car contains the same 

 equipment when being weighed loaded and empty. 



ACCURACY OF WEIGHTS. 



All things considered, weights obtained on track scales in proper 

 condition and located under cover are subject to fewer chances for 

 error than weights obtained by any other method. The load is 

 weighed in one draft, which oA T ercomes the danger of omitting the 



Fig. 8. — Broken bales, showing how losses may occur in terminal markets. 



weights of any draft, as is possible when weighing on platform or 

 wagon scales. 



The tare is also obtained in one draft, frequently without any 

 movement of the car from the time the gross weight was obtained, 

 so that about the only chance of error is in tabulating the weight. 

 If a registering beam is used, this chance of error also is eliminated. 



Because of the great cost of track scales, however, and the fact 

 that their use would be confined in most cases to one warehouse, they 

 are frequently impracticable and generally can not be maintained, 

 except by railroads or large concerns. 



CERTIFICATES FOR TRACK SCALE WEIGHTS. 



Certificates of weights for track scales should differ but little from 

 other weight certificates, but since the weight is obtained in one 



