AND THE ATMOSPHERE. 211 



more evidence were wanting to show that the 

 pressure of water is not according to its per- 

 pendicular height, I would appeal to the hy- 

 drostatic balance. When a substance of any 

 given magnitude is placed in the pan, which is 

 suspended in the air, it will balance the sub- 

 stance in the pan under the surface of the water ; 

 the weight of the substance in the water, does 

 not increase in proportion to the depth of the 

 water in which it is immersed. The same 

 quantity of matter in the scale, which is placed 

 and suspended in the air, will balance the mat- 

 ter in the one which is situated under the sur- 

 face of the water, as perfectly at the depth of fifty 

 fathoms, as it will do at the depth of one. The 

 pressure at the bottom, therefore, is not greater 

 than it is near the top. The pressure of the water 

 upon the under part of the scale, is exactly the 

 same, as the pressure upon the upper part of it ; 

 and by being pressed equally in every direc- 

 tion, it remains suspended, and balanced, in 

 whatever part of the water it is situated. Not- 

 withstanding these most obvious truths, the 

 principles on which the science of hydrostatics 

 depends, are in direct violation of them. I 

 cannot expose the error of these principles 

 more effectually, than by quoting them as 

 they are expressed by authors and teachers 

 in general. 



