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MECHANICS AND USEFUL ARTS. 93 



and it was difficult to believe the statement that it would take rocks of five 

 tons' weig-ht out of the ground without digging around them. 



But seeing is believing; and we have witnessed the machine in actual 

 operation, taking out boulders weighing from one to five tons, and from 

 one-half to seven-eighths under ground, at the rate of one every three min- 

 utes. The machine is a compact and stout iron windlass, on wheels, drawn 

 by one pair of oxen, while another pair, immediately in front of them, are 

 hitched to a rope which works the windlass through cog-wheels, multiply- 

 ing the power some twenty times. The windlass can also be worked by 

 hand, in which case the power is multiplied twice or three times as much. 

 Two very heavy chains are fastened to and reeled upon the barrel of the 

 windlass; they support a hook in whose jaw is hung a piece of chain, which 

 can easily be lengthened or shortened. This chain is reeved through the 

 shanks of the huge hooks which take hold of the rocks. The rocks are 

 previously fitted for the machine by drilling holes in opposite sides, about 

 three-quarters of an inch deep. The machine is driven over a rock; the 

 man at the windlass which is so high that a rock of five or six tons can be 

 lifted two feet from the ground lowers the great grappling hooks; the 

 man below adjusts their points in the holes in the sides of the rocks, length- 

 ening or shortening the chain holding the hooks as the rock is larger or 

 smaller; the man at the windlass then tightens the slack, while the man 

 below gets upon the machine; then both heave at the windlass. If they 

 do not start the rock, the driver helps them, and if the three cannot, it is 

 given up as liable to break the machine. If they do start it, they tell the 

 driver to go ahead, and he drives on the forward team, winding up the 

 windlass. The rock rises out of the ground, and the team yoked to the 

 machine then draws it wherever it is wanted. It can be laid as the bottom 

 stone of a wall, or, if the bottom stones are laid, the machine can be backed 

 up to the wall, and the rock pulled over by the other pair of oxen, and laid 

 on the wall. 



This all seems very simple and easy, and it is easier than it seems. The 

 holes drilled in the rocks were so shallow that we were expecting all the 

 while that the hooks would slip, or would break away the rock, when the 

 enormous lifting power required to lift it and tear away the earth which 

 wedged many of them down came to be applied. But they did not, and in 

 some cases the hooks were applied even without drilling holes for them. It 

 is a wonder that, among all the inventive Yankees who have spent so many 

 lifetimes digging out rocks with spades, and levers, and chains, and oxen, 

 nobody should have thought of this before. Mr. S. E. Bolles, of Plymouth, 

 Mass., the inventor of the machine, got his patent for it five years ago; but 

 it is only lately, and through an enterprising farmer, that it has been 

 brought to the notice of the public. The machines appear to be very sol- 

 idly built. Thej' weigh a little over a ton, and cost, aside from the patent 

 right to use them, two hundred and twenty-five dollars. Messrs. Knapp & 

 Co. offer to take out all the rocks weighing between one and five tons, on 

 any oi'dinary piece of ground in the counties for which they hold the patent 

 right, at seventeen dollars per hundred. They say it costs three or four 

 times as much to do it in the old way, and that many pieces of ground, 

 Avhich would not pay for clearing up in the old way, can now be smoothed 

 off at a profit. 



