ink Cramer— JReoent Rook Flexure. 221 



The mill contains i v or 20 large and heavy pulp grinders, 

 U machine employing two water wheels. These grinders 

 were set in a row. extending through the whole length of the 

 mill about midway between the long walls; and they were all 

 at exactly the same level. After the accident, the first 

 machine (a, fag. 1). next the cement pier, stood an inch above 

 the level of the long row of undisturbed machines in the south- 

 east vnd of the mill ; the second {/>) had been raised \{ inch.-, 

 the third 3| inches, the fourth 4-j inches, the fifth 8-J inches, 

 the sixth L| inches, the seventh | of an inch and the eighth s 

 of an inch. The set <>( figures indicating the amounts to which 

 the first eight machines were lifted, is as symmetrical as the 

 of cracks in the northeast wall ; and the fourth machine, 

 which is lifted most, lies in a straight line with the perpendic- 

 ular crack in the northeast wall and the gaping crack in the 

 pier. The axis of the disturbance passed in a straight line 

 under the mill, diagonally across the north corner. Its direc- 

 tion is nearly northwest and southeast, and parallel with the 

 course of the river between the two bends. 



The character of the disturbances and their intimate connec- 

 tion compel the conclusion that they were all produced by a 

 single force. The crack in the cement pier alone might have 

 been produced by the sagging of its lower end; but the appli- 

 cation of the simple laws of force to the set of cracks in the 

 northeast wall, proves that the force that produced them acted 

 perpendicularly upward. The inclined cracks need only be 

 extended to form two sides of the parallelogram of forces, an;l 

 the perpendicular crack becomes the diagonal that indicates 

 the direction of the force, the components of which produced 

 the inclined cracks. To assure himself beyond a doubt that 

 the mill had not given way, Mr. OTveefe, the gentleman 

 who had charge of its erection, ran the levels again from the 

 benchmark that was used to secure those levels when the mill 

 was built, and found that nothing in the whole mill was below 

 the level at which it had been placed. A bulge w r as formed 

 in the floor, and its axis connected the cracks in the pier and 

 the northeast wall ; and there is a similar bulge in the roof. 

 The cracks, the figures indicating the distances to which the 

 machines were raised, and the other facts mentioned prove 

 beyond a doubt that the axis of disturbance was an axis of 

 uplift ; and that the damage was done by the formation of 

 a nearly symmetrical ridge in the bed-rock. The mill was 

 built on the Galena limestone, which forms the bed of the 

 Lower Fox River at that point. The uppermost layer, on 

 which the walls and piers were set. is two and a half feet thick, 

 and dips to the southeast one foot in two hundred and forty- 

 eight. This layer was nowhere broken and everywhere nearly 



