XVI CONTENTS. 



a fluid, is equal to the weight of the displaced and superincumbent fluid, art. 246, 

 page 222. The difference between the downward and upward pressures, is equal 

 to the difference between the weight of the solid and an equal bulk of the fluid, 

 art. 247, page 222. Absolute and relative gravity, what, art. 248, pages 222 and 

 223. By absolute gravity, fluids gravitate in their proper places, by relative 

 gravity they do not, ib. A heavy heterogeneous body descending in a fluid, has the 

 centre of gravity preceding the centre of magnitude, art. 249, page 223. The 

 reason of this, ib. Concluding remarks, art. 250, page 223. The force with which 

 a body ascends or descends in a fluid of greater or less specific gravity than itself, 

 is equal to the difference between its own weight and that of the fluid, art. 251, 

 pages 223 and 224. The force of ascent and descent is nothing when the specific 

 gravities are equal, art. 251, page 224. When a body is suspended or immersed in 

 a fluid, it loses the weight of an equal bulk of the fluid in which it is placed, art. 

 252, page 224. When a body is suspended or immersed in a fluid of equal or 

 different density, it loses the whole or a part of its weight, and the fluid gains the 

 weight which the body loses, art. 253, page 225. Bodies of equal magnitudes 

 placed in the same fluid lose equal weights, and unequal bodies lose weights pro- 

 portional to their magnitudes, art. 254, page 225. The same body placed in 

 different fluids, loses weights proportional to the specific gravities of the fluids, 

 art. 255, page 225. When bodies of unequal magnitudes are in equilibrio in any 

 fluid, they lose their equilibrium when transferred to any other fluid, art. 256, page 

 225. When a body rises or falls in a fluid of different density, the accelerating 

 force, what, art. 257, page 225. When the solid is heavier than the fluid it 

 descends, when lighter it ascends, art. 258, pages 225 and 226; hence relative 

 gravity and relative levity, ib. Practical rule for the general formula, art. 259, 

 page 226. Example for illustrating ditto, art. 260, page 226. The distance of 

 descent determined, when the pressive and buoyant forces are equal, art. 261, pages 

 226, 227, and 228. Practical rule for calculating ditto, art. 262, page 228. 

 Example for illustrating ditto, art 263, page 2'J8. 



CHAPTER X. 



OF THE SPECIFIC GRAVITIES OF FLUIDS, AND THE THEORY OF 

 WEIGHING SOLID BODIES BY MEANS OF NON-ELASTIC FLUIDS. 



Introductory remarks on specific gravity, end the principles or criteria of com- 

 parison, page 229. The weight lost by a body, is to the whole weight, as the 

 specific gravity of the fluid is to that of the solid, art. 264, pages 229 and 230. 

 The weight which the body loses in the fluid is not annihilated, but only sustained, 

 art. 264, page 230. The weight of a body after immersion determinable, art. 265, 

 page 231. Practical rule for ditto, ib. Example for illustration, art. 266, page 231. 

 - The weights which a body loses in different fluids, are as the specific gravities of 

 the fluids, art. 266, corol. page 231. The real weight of a body determinable by 

 having its weight in water and in air, art. 267, pages 231 and 232. Practical rule 



for ditto, art. 268, page 232. Example for illustration, art. 269, page 232. The 



specific gravity of a body determinable from its weight, as indicated in water and 

 in air, art, 270, pages 233 and 234. Practical rule for ditto, art. 271, page 234. 



