222 



Frank Cramer — Recent Rock Flexure. 



2. 





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plane when the foundations were laid. An unsuccessful at- 

 tempt was made to examine this layer after the accident by 

 means of a protected electric light. But by careful sounding 

 it was found that this uppermost stratum is no longer plane. 

 Along the inside of the cement pier opposite the crack, the 

 water is not so deep by a whole foot as it is in the neigh- 

 boring parts of the tail-race; but from this point it grows 

 gradually deeper in both directions. This ridge (c, fig. 2), can 

 be traced, but not so clearly, diagon- 

 ally across to the northeast wall, and 

 its axis is the same as that of the dis- 

 turbances above. Although there was 

 no evidence of a general crushing, 

 irregular, thin ; freshly broken pieces 

 splintered from the thick upper laver Fi s- 2 - Section of ridge: a, 



x i -i, ixi x, water; bo, limestone. 



were brought up by the man who was 



sent into the water soon after the accident to examine the rock 



bottom. 



Under the floor of the mill there is a row of iron beams that 

 supplement the stone piers that support the floor and machines. 

 The beams that stand on the ridge are bent (d, fig. 3) ; while 

 one of them, in the deeper water just beyond the ridge, is not 

 only not bent but stands straight 3. 



and loose in the water (e, fig. 3). 

 About 250 feet from the mill 

 there is a new artesian well 225 

 feet deep. It was flowing at 

 the time of the accident, but 

 not more than three minutes 

 afterward it had stopped and 

 did not start again until several 

 weeks later, when the pipe was 



given a few blows at its Upper at right angles to fig. 2 : a, floor; c, lime 



end. It then began to deliver s i°. ne ; d > <*. e > iron P illars - 

 water again, but in diminished quantity. Edwards and Orbi- 

 son, the civil engineers, report that when they built the dam 

 that furnishes the power for the mill, a year ago, they found 

 in the river bed two lines of fracture and crushed rock, and 

 that these lines of fracture in the bed rock are parallel with 

 the axis of the recent disturbances. 



The character of the cracks in the walls, the fact that the 

 first eight machines, which lie between the breaks in the pier 

 and the northeast wall, are lifted above the level at which they 

 were set, the distances to which those machines were lifted, 

 the bulging of the floor and roof, the ridge in the rock under 

 the mill, the condition of the iron supports under the floor, 

 and the fact that nothing in the mill is below the level at 



Water 



Fig. 3. Section of mill floor and ridge, 



