HYDRAULICS AND HYDROSTATICS. 237 



the height marked by the horizontal line marked in the cut, 

 which is a little above the upper ends of the four tubes ; it 

 will be found that the liquid will pass laterally into the 

 tube, C, ascend directly in D, and circuituously in E, while it 

 first descends and then ascends in F, rising equally in all the 

 tubes, and spouting out till the water is reduced in the side 

 tubes to the level of the summits of the internal ones, when, 

 the equilibrium being established, the liquid will remain at 

 rest. Thus, it follows, that any number of columns of a 

 liquid, freely communicating, whatever may be their re- 

 spective diameters and figures, will always have the same 

 vertical height. Price, $2.50 and $4.00. 



Hydrostatic Equilibrium. (Fig. 257.) Another appa- 

 ratus to exhibit the same effect as the last, in which a small 

 column of water supports a much larger quantity. 



Price, $3.00 



Fig. 257. Fig. 258. 



Hydrostatic Paradox. Fig. 258 consists of a pair of scales 

 mounted on a brass stand, having a wide mouthed glass jar, 

 or cup. suspended from one end, and the other end having 

 the usual scale pan. On the pillar supporting the scales, 

 there is a brass slide with a milled-head screw for fastening 

 it at any height required, to which there is an arm bearing 

 a round block of wood loosely fitting the glass vessel. To 

 use, let the jar, nearly filled with water, be poised by loading 

 the opposite pan with the requisite weights ; then after 

 marking exactly the height the liquid stands, pour out a 

 part of it and immerse the block of wood, supported by the 

 arm free from the sides and bottom, just deep enough to 

 raise the remaining liquid to the same height as at first, at 

 which it is screwed fast, when the balance will be again 



