302 ATMOSPHERICAL PRESSURE, &C. 



transition from one ataiospheric pressure to 

 another ; and unless a change of volume take 

 place, we cannot feel any pressure, either inward 

 or outward. The phenomena of the water- 

 hammer shew, that the particles of water are 

 hard, as they strike each other like flint and 

 steel; and it is exceedingly probable that other 

 bodies, solids as well as liquids, are constituted 

 in like manner. A general pressure on the 

 system then, only increases in a small degree 

 the attraction of the ultimate particles, and it 

 is met by a corresponding increase of repulsion 

 from the atmosphere of heat ; so that the system 

 remains, as nearly as possible the same, and 

 unaffected by such pressure. 



I can scarcely forbear observing on the present 

 occasion the absurdity of those who remark, 

 that all people might swim, and that it is only 

 from fear or ignorance of the art, that some 

 fail in the attempt. When we see that some 

 persons are heavier than water, and others only 

 .8 of that weight, it would be just as plausible 

 for a piece of deal to upbraid a piece of lignum 

 vit(B with the inability to swim, from fear, or 

 from want of skill in the art, which the deal 

 considered of easy acquisition. 



