124 BR AMAH'S PRESS. 



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 working ; but as it is only men 

 who, like Bramah, understand the properties of 

 substances well, and are at the same time very in- 

 genious as mechanics, that can apply those princi- 

 ples to useful purposes, we, who are not so gifted, 

 can often understand the great principle in nature, 

 from the small application 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 tuns 

 . 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 

 water than is contained in an ordinary mill-pond. 

 It is true that if we were to try such an experiment 

 we should have some difficulty in finding a cylinder ; 

 because it would give way, and give way with a 

 dreadful explosion, if it were not, at its very weakest 

 point, more than able merely to balance the weight 

 of the vast fleet or the entire hill. With us such 



