214 PROPERTIES OF AIR 



propositions by mathematical demonstration, 

 false conclusions are drawn in violation of the 

 demonstration itself; after stating it as an 

 evident truth, that the particle 1. can affect the 

 next particle 2. only by the pressure every 

 way; which, therefore, is as 1. and the par- 

 ticle 2. will react upwards upon the particle 

 1. with a force which is as 1. it is then 

 falsely asserted, that the particle 2. acts 

 on the particle 3. by pressure doivnivards with 

 two degrees of force, arising from its own 

 weight, and that of the particle above it. So 

 far, however, from this conclusion being justi- 

 fied by the fact, facts universal falsify the 

 conclusion. I will maintain it as an undeniable 

 and universal truth, that opposing forces equally 

 balanced, destroy each other, wholly and to- 

 tally ; that not only if a body is acted upon by 

 three forces, which are proportional to, and in 

 the direction of, the three sides of a triangle, 

 the body will be kept at rest ; but that it will 

 be more especially the case, if these forces act 

 equally from a centre, towards the whole of 

 the circumference, or vice versa. If, for exam- 

 ple, four powers, of whatever description they 

 may be, (whether they be four weights, four 

 levers, or four elephants,) exert equal force 

 in opposite and contrary directions, the effect 

 of the whole is absolutely lost, by the separate 

 power of each. If equal bulks of matter, whose 



