116 BRAMAH'S PRESS. 



in water, so as to take note of their magnitude, 

 the column of water which moves in the cylinder 

 of Bramah's press, is the same as a screw, the 

 threads of which can be made finer than we can 

 know or even imagine. Thus, as there is no limit 

 to the slowness of the motion of the water, there is 

 none to the greatness of the power of the press. 

 We shall see in a future section how powerful and 

 general an instrument water is in nature's work- 

 ing ; but as it is only men who, like Bramah, un- 

 derstand the properties of substances well, and 

 are at the same time very ingenious as mechanics, 

 that can apply those principles to useful purposes, 

 we, who are not so gifted, can often understand 

 the great principle in nature, from the small appli- 

 cation of it by man, better than we can from nature 

 itself. The principle of the press is this : water is 

 forced into a large cylinder through a very small 

 pipe ; and, without making allowance for the friction, 

 the pressure on the cylinder is as many times that 

 on the pipe, as the surface of the cylinder contains 

 that of the pipe. If, for example, the little pipe 

 through which the water were forced in, had its 

 bore something less than one tenth of an inch in 

 diameter, and if the cylinder that received the 

 water were about the size of one of the gasometers 

 at the large gas-works, one man forcing in the 

 water with the pressure of a single hundred weight, 

 would communicate so much to the water in the 

 cylinder as that it would raise up ten thousand 

 ships of about three thousand tons each, or move 

 Highgate Hill in one mass ; and all that power 

 would be obtained by the application of a very 

 simple principle, of whose operation there are 

 countless instances in nature, together with less 



