Chat. XIV.

ON PILES AND PILE-DRIVING.

1077

per minute; the circumference of the cylinders winding up 3 feet of rope at each turn, itwould raise the ram 7 feet 6 inchesper minute, and the blow given tothe pile would be equivalent to200,000 pounds at least.

The pile-driving engine now inuse is upon a very superior prin-ciple to those we have described;instead of having the ram of oakthat was required to be hoopedround in various directions to pre-vent its splitting, it is formed ofcast-iron or bronze ; the latter me-tal possessing greater elasticity issupposed to contribute to the driv-ing of the pile; after the ram hasbeen raised to its destined ele-vation by means of a crab or wind-lass, it is released by pulling a ropethat opens the nippers attached atthe top of it, when it falls withconsiderable weight on the top ofthe pile-head. The ram is main-tained in its vertical position by aframe at the back.

Pile-driving Machine used atMontrose Harbour was attachedto the steam-engine, and of ingeniousconstruction. The ram weighed12 cwt., and the clipper, with itsslider, was of the ordinary kind,except that the upper part of theclipper had its extremities made ofa sufficient length to allow the sliderto rise 15 inches after the ram hadbeen disengaged by the slips. Theram chain, which was shackled tothe clipper, passed over one pulleyat the top of the guides, to anotherpart of the machine, by means ofanother pulley placed at the base ofthe guides.

As the ram may be supposed tofall 16-,'j feet in a second, we maycalculate its velocity in fallingthrough any given height, as pro-portionate directly to the time ofdescent; the velocity acquired atthe end of the first second is equal to 32^ feet per second, upon which principle the follow-ing table has been calculated, by which the force of the blow of any ram whatever

o 2

"5 5

•U 3

2s ■

It s

II*

Force In Tons ofu Ham weighing

1 Ton.

® e>x.«

o s

^5 s

Time of theDescent inSeconds.

Force in Tons ofa Ham weighing

1 Ton.

Fall of theHam in Feet .

Time of theDescent inSeconds.

Force in Tons ofa Ham weighing

1 Ton.

Fall of theHam in Feet.

9 „

lb |JUm

n

Force in Tons ofa Hum weighing

1 Ton.

1

•25

8-0

11

•83

26-6

21

1*14

36-7

31

1-39

44-6

2

•35

11-3

12

•86

27-8

22

1-17

37 6

32

1-41

454

3

•43

13-9

13

•90

28-9

23

1-20

38*5

33

1-43

46-1

4

•50

16*0

14

•93

300

24

1 *22

S9-3

34

1*45

46-8

5

‘56

17-6

15

•96

310

25

1-25

40*1

35

1-48

47-4

6

•61

19-6

16

1-00

32-1

26

1*27

40-9

36

1*50

48-1

7

•66

21*2

17

103

33-1

27

1*29

41*7

37

1-52

488

8

•70

22-7 |

18

1 05

340

28

1-32

42*4

38

1-54

49*4

9

•75

24-1 i

19

1 09

35 0

29

1 *34

43-2

39

1-56

501

10

•79

25-3 !

20

1-11

35 9

30

1-37

13-9

40

1-58

50-7

3 z 3

Fig. 1647.

PILE-DRIVING ENGINE.