440 POPULAR LECTURES AND ADDRESSES. 



two ships, one of them with a cutting grapnel, and 

 the other (the Great Eastern herself) with a holding 

 grapnel. This plan was illustrated by lifting, by 

 aid of two grapnels, a very fragile chain (a common 

 brass chain in short lengths, joined by links of fine 

 cotton thread) from the floor of the Royal Society. 

 It was also pointed out that it can be executed by 

 one ship alone, with only a little delay, but with 

 scarcely any risk of failure. Thus, by first hooking 

 the cable by a holding grapnel, and hauling it up 

 200 or 300 fathoms from the bottom, it may be 

 left there hanging by the grapnel-rope on a buoy, 

 while the ship proceeds three miles westwards, cuts 

 the cable there, and returns to the buoy. Then, it 

 is an easy matter, in any moderate weather, to 

 haul up safely and get the cable on board. 



The use of the dynamometer in dredging was 

 explained ; and the forces operating on the ship, 

 the conditions of weather, and the means of 

 keeping the ship in proper position during the 

 process of slowly hauling in a cable, even if it were 

 of strength quite insufficient to act, when nearly 

 vertical, with any sensible force on the ship, were 



