MECHANICS AND USEFUL ARTS. 39 



bored for the purpose through the windlass. Preparatory to this, a long 

 rope, fastened to the windlass, had been wound around it; and this rope is 

 now pulled upon, and the suspending ropes are in consequence wound round 

 the windlass, and kept tight by securing the winding rope. The pulleys by 

 which the boat has been raised are unhooked, and she is left suspended to 

 the davits. For the purpose of lashing the boat to the ship, there arc on 

 each davit two iron prongs, one nearly as high as the gunwale of the boat, 

 and the other two feet lower than her keel. These prongs extend directly 

 downward, so that any ring or thimble passed up them would fall by ils 

 own weight, if lefc unsustaincd. Ropes with thimbles at their ends arc next 

 hooked to the prongs, those from the upper prongs being passed over the 

 nearest side of the boat, those from the lower ones under her and over the 

 other side, while all four are tightly fastened inside of her. The boat is now 

 suspended, prevented from rocking and ready for service. The process of 

 lowering is obvioi.'.s ; a man enters the boat, unfastens the winding rope, 

 which he allows ta run fast or slow as he pleases. The weight of the boat 

 unwinds the suspending ropes, which finally slip from the holes in the wind- 

 lass and remain hanging from the davits. The thimbles of the lashing 

 ropes in the mean time slip from the prongs and remain hanging from the 

 sides of the boat. In this operation the force of a man is made sufficient to 

 control the weight of a boat by means of the friction pulleys above men- 

 tioned, the effect of which is analogous to that of a turn or two of a rope 

 around a post, as exemplified every day on the arrival of a steamer, when 

 one man by this process checks the motion of a boat of a thousand tons. 

 The friction pulley consists of a block with three sheaves placed one above 

 the other, their centers in a straight line, their sides on the same plane and 

 their axles parallel. The rope is made to wind its way from the right of 

 one sheave to the left of the next, and once on, has the shape of a cross sec- 

 tion of a hollow rail. The nearer the sheaves are to each other the sharper 

 the turnings of the rope, and the stronger the resulting friction. Another 

 precaution which it is always prudent to take beforehand, is that of fasten- 

 ing the helm on the proper side for turning the head of the boat away from 

 the ship. But this must be done carefully, for if it be turned too much on 

 that side and the boat lowered from a steamer at full speed, mishaps might 

 occur. This invention has been thoroughly tried on board several vessels of 

 the English Navy. It is found to answer beyond expectation, and is now 

 adopted by the Admiralty. 



STEAM OX COMMON ROADS. 



Considerable attention has been excited in New York during the past year 

 by the occasional appearance on Broadway of a street locomotive, built by 

 Mr. Richard Dudgeon. Its speed was about equal with the average speed 

 of horses in stages, and it was apparently controlled with as much ease, and 

 with more certainty. The popular notions that horses would be alarmed by 

 such vehicles, and that they cannot ascend hills on account of their wheels 

 slipping, were refuted by the performance of this engine, which met with no 



