OF THE PILE-ENGINE. 105 



Fig. 3.) that takes hold of the ram Q by the staple R LECT. 

 for drawing it up. D is a spiral or fusy fixed to the \^v^ 

 drum, on which is wound the small rope that goes 

 over the pulley U, under the pulley V, and is fastened to 

 the tope of the frame at 7. To the pulley block V is 

 hung the counterpoise W, which hinders the follower 

 from accelerating as it goes down to take hold of the 

 ram : for, as the follower tends to acquire velocity in its 

 descent, the line T winds downwards upon the fusy, on 

 a larger and larger radius, by which means the counter- 

 poise Wads stronger and stronger against it; and so 

 allows it to come down with only a moderate and uni- 

 form velocity. The bolt Y locks the %um to the great 

 wheel, being pushed upward by the small lever 2, which 

 goes through a mortise in the shaft A, turns upon a pin 

 in the bar 3 fixed to the great wheel B, and has a 

 weight 4, which always tends to push up the bolt Y 

 through the wheel into the drum. L is the great lever 

 turning on the axis m, and resting upon the forcing bar 

 5, 5, which goes down through a hollow in the shaft A, 

 and bears up the little lever 2. 



By the horses going round, the great rope H is 

 wound about the drum C, and the ram Q is drawn up by 

 the tongs F in the follower G, until the tongs comes 

 between the inclined planes E ; which, by shutting the 

 tongs at the top, opens it at the foot, and discharges the 

 ram, which falls down between the guides b b upon the 

 pile P, and drives it by a few strokes as far into the mud 

 as it can go ; after which, the top part is sawed off close 

 to the mud, by an engine for that purpose.* 1 Immedi- 

 ately after the ram is discharged, the piece 6 upon the 



Note 41. When the piles are driven for the purpose of constructing a cot 

 fer-dam, they may be afterwards raised by the hydrostatic press of Bra- 

 mah. The plan has been successfully adopted in many cases, and its 

 advantage over our author's mode of sawing them beneath the water, 

 will be sufficiently obvious, when we come to a description of that in- 

 strument. 



