HYDROSTATICS. 425 



c, or any other place in the tube abode, you will find 

 it just as high as the tube/: and if you pour in water 

 to fill the first tube, the second will be filled also. 



Now it is evident that the water rises in the tube f, 

 from the downward pressure of the water in the tube 

 abode, on the surface of the water, contiguous to the 

 inside of the top of the box ; and as k will stand at 

 equal heights in both tubes, the upward pressure in the 

 tube/ is equal to the downward pressure in the other 

 tube. But, if the tube /were put in any other part of 

 the top of the box, the rising of the water in it would 

 still be the same : or, if the top was full of holes, and a 

 tube put into each of them, the water would rise as high 

 in each tube as it was poured into the tube abode ; and 

 then the moveable bottom would have the weight of the 

 water in all the tubes to bear, besides the weight of all 

 the water in the box. 



And seeing that the water is pressed upward into 

 each tube, it is evident that, if they be all taken away, 

 excepting the tube abed e, and the holes in which they 

 stood be stopt up ; each part, thus stopt, will be pressed 

 as much upward as was equal to the weight of water in 

 each tube. So that, the upward pressure against the 

 inside of the top of the box, on every part equal in 

 breadth to the width of the tube abode, will be pressed 

 upward with a force equal to the whole weight of water 

 in the tube. And consequently, the whole upward 

 pressure against the top of the box, arising from the 

 weight or downward pressure of the water in the tube, 

 will be equal to the weight of a column of water of the 

 same height with that in the tube, and of the same 

 thickness as the width of the inside of the box : and this 

 upward pressure against the top will re-act downward 

 against the bottom, and be as great thereon, as would 

 be equal to the weight of a column of water as thick as 



