PRESSURE OF WATER. 6 1 



vessel is the same, and depends upon the depth of the water If we subject 



Fig. 62. Water Press. 



Figs: 58, 59, 60, 61. Pressure of Water. 



a portion of the liquid surface to certain force, this pressure will be 

 dispersed equally in all directions, and from an acquaintance with this fact 

 the Hydraulic Press was brought into notice. If a vessel with a horizontal 

 bottom be filled with water to a depth of one foot, every square foot will 

 sustain a pressure of 62*37 Ibs., and each square inch of 0*433 Ibs. 



We will now explain the principle of this WATER 

 PRESS. In the small diagram, th.e letters A B represent 

 the bottom of a cylinder which has a piston fitted in it 

 (p). Into the opposite side a pipe is let in, which leads 

 from a force-pump D, which is fitted with a valve E, 

 opening upwards. When the piston in D is pulled up 

 water enters through the valve ; when the piston is 

 forced down the valve shuts, and the water rushes into 

 the chamber A B. The pressure pushes up the large piston with a force 

 multiplied as many times as the area of the small piston is contained in the 

 large one. So if the large one be ten 

 times as great as the small one, and the 

 latter be forced down with a 10 Ib. 

 pressure, the pressure on the large one 

 will be 100 Ibs., and so on. 



The accompanying illustration 

 shows the form of the Hydraulic or 

 Bramah Press. A B C D is a strong 

 frame, F the force-pump worked by 

 means of a lever fixed at G, and H is 

 the counterprise. E is the stop-cock to 

 admit the water (fig. 63). 



The principles of hydrostatics will 

 be easily explained. The Lectures of 

 M. Aime Schuster, Professor and Libra- 

 rian at Metz, have taught us in a very 

 simple manner the principle of Archi- 

 medes, in which it is laid down that " a 

 body immersed in a liquid loses a por- 

 tion of its weight equal to the weight 

 of the liquid displaced by it." We take 



** 



Fig. 63. Bramah Press. 



