DEAIlSrAGE METHODS FOR COUNTY ROADS. 



33 



water to be drained off, the diameter of the tile never should be less 

 than 4 inches, because experience has shown that tile having a smaller 

 diameter is very liable to become obstructed by sediment. The larger 

 diameters given in the table generally are used only where it is neces- 

 sary to admit more or less surface water directly into the tile, or to 

 provide for some unusual flow from springs. 



CLAY TILE. 



Clay tile of the diameters shown in Table 4 is manufactured in 

 almost every section of the United States. The ordinary farm tile, 

 without the bell joints, is the kind most generally used f or subdraining 

 roads, and is generally satisfactory when laid at the side of a road 

 where it will not be subjected to heavy loads. The tile may be either 

 round or hexagonal in cross section and should be straight longi- 

 tudinally, well burned, and free from cracks. The nominal section 

 lengths are 12 inches for the smaller sizes and 2 feet or 2 feet 6 inches 

 for the larger sizes. In practice, the lengths generally are made 

 slightly in excess of the nominal to allow for a small amount of break- 

 age. The ends always should be cut square in manufacturing so that 

 successive sections may fit together snugly, but seldom does this con- 

 dition exist. To make a good fit it is necessary at the time of laying 

 to turn the tile over until the ends make the snuggest joint. If the 

 cost of bell tile is not prohibitive they may be used to advantage in 

 place of butt-joint tile. 



Table 8 gives the average weight and the average number of feet 

 in a carload for the various diameters of field tile. The costs at the 

 factory are subject to more or less variation, and freight charges on 

 tile have been relatively high, so that the costs of pipe delivered at 

 railroad points some distance from the factory are so constantly 

 variable that tabular figures are of little value. Where more than one 

 size of tile is shipped at the same time, the amount in a carload may 

 be increased and the freight per ton decreased by nesting the differ- 

 ent sizes. 



Table S. — Cost and tceight of drain tile. 



Inside diameter. 



Average 

 cost per 

 1,000 feet 

 f. 0. b. 

 factory. 



Average 

 weight 

 per foot. 



Average 



number 



of feet 



in a 



carload. 



Inside diameter. 



Average 

 cost per 

 1,000 feet 

 f. 0. b. 

 factory. 



Average 

 weigtit 

 per foot 



Average 



number 



of feet 



in a 



carload. 



Inches. 

 4 



S15. 00 

 22.50 

 27.50 

 47.00 

 67.00 



Pounds. 

 8 

 10 

 12 



18 

 28 



6,500 

 5,000 

 4,000 

 2.500 

 1,600 



Inches. 

 12 



$95.00 

 140. 00 

 245. 00 

 370. 00 



Pounds. 

 36 

 50 

 72 

 115 



1,000 



5 



15 



700 



.6 



18 



400 



8 



24 



300 



10 







66998°— 18— Bull. 724— -3 



