of Liquids to each other. 315 



Having found a way of placing in the middle of this 

 small hemispherical mass of water little isolated solid 

 bodies which displaced a great part of the liquid with- 

 out being wet by that which remained, this arrange- 

 ment produced no change, either in the exterior form 

 or in the dimensions of the little hemisphere, or in the 

 force displayed in resisting the pressure of the more 

 elevated column of water in the other arm of the 

 siphon. 



NOTE. 



(See page 303.) The following calculation, which is neither long 

 nor difficult to follow, may be of service in understanding what has 

 just been advanced. 



A cubic inch of water, English measure, weighs 253.175. grains 

 Troy ; consequently a spherical mass of this liquid 10.8233 inches in 

 diameter, and which would have a surface of 368 square inches, would 

 weigh 168,060 grains. And since the specific gravity of gold is to 

 that of water as 192,581 is to 10,000, a sphere of gold of the same 

 diameter would weigh 3,236,525 grains in vacuo. 



Now, a similar sphere weighed in water would lose of its weight 

 in vacuo an amount equal to the weight of a mass of water of a volume 

 equal to that of the sphere. It would weigh, therefore, 3,236,525 

 168,060 = 3,068,465 grains, a deduction being made for the slight 

 amount of its weight which it would lose on account of the viscos- 

 ity of the liquid. 



Since the surface of the globe is equal to 368 square inches, we see, 

 from the result of the experiment of which we have just given an 

 account, that this decrease of weight must be exactly one grain. 

 Consequently the sphere suspended in water will weigh on the beam 

 of the balance only 3,068,464 grains, and it will lose ^ of its 

 weight on account of the viscosity of the liquid. 



Let us suppose, now, that the diameter of this sphere were 10 times 

 as small, or 1.08233 inches, and let us see according to what law the 

 effect produced on the viscosity of the liquid will be increased by this 

 diminution of volume. 



The volumes and consequently the weights of spheres of different 

 diameters being as the cubes of those diameters, while their surfaces 



