6 BULLETIN" 86, U. S. DEPARTMENT OF AGRICULTURE. 



None of the hoops failed during the test. A f-inch oak barrel 

 should probably have not less then eight hoops of the sizes of those 

 used on the barrels tested, as the swelling of the wood might break 

 the hoops. 



Variation in strength of barrels of the same design is due in large 

 measure to the variability of the wood composing the head and 

 staves. Test specimens taken from these barrels show that some of 

 the staves may have less than one-fourth the strength of others. (See 

 Table 1, p. 4.) Evidently no attempt had been made to grade the 

 staves on the basis of strength, the only criterion of fitness being that 

 the staves should be clear and straight grained. The dry weight per 

 cubic foot of clear straight-grained wood is a splendid guide as to 

 probable strength, the heavier, denser wood being the stronger. The 

 advisability of grading staves and heading with reference to the 

 strength might well be considered. 



TESTS OF MADE-UP BARRELS. 



BARRELS. 



In order to try out the effect of some of the changes in design as 

 suggested above, barrels were made up with f -inch staves, f-inch head, 

 and eight hoops. The staves and hoops were from the two 8-hoop, 

 f-inch barrels, the heads from f-inch barrels and previously tested 

 under internal pressure. In order to make these heads fit, it was 

 necessary to joint fifteen-sixteenths inch off of one stave of each 

 barrel. The bilge and quarter hoops were not changed, but were 

 permitted to drive farther onto the barrels. The head hoops were 

 shortened H inches and were driven flush with the ends of the staves. 

 (In the original tests the head hoops were driven beyond the ends of 

 the staves, as shown in I and II of fig. 1 .) The spacing of the hoops, 

 weight, capacity, etc., of these barrels are shown in III, figure 1. 

 In assembling the barrels the hoop joints were placed at random. 



INTERNAL-PRESSURE TESTS. 



The two made-up barrels were tested under internal pressure. The 

 results of these tests showed them to be fully equal to the barrels 

 with f-inch heads and staves. One of these barrels withstood a 

 pressure of 34 pounds per square inch up to the time the head began 

 to fail, when the pressure was released. The increased capacity of 

 the barrel under this pressure, due primarily to the springing of the 

 heads, was 8} pounds of water. On release of the pressure the barrel 

 resumed its original form with no apparent leakage. 



The head of the second barrel was broken out by a pressure of 38 

 pounds per square inch. 



Neither of these made-up barrels showed any leakage between the 

 staves during the tests. 



