ON SIPHONS AND JETS OF WATER. 40? 



ingenious paper on the Phenomena of Earthquakes, published a few 

 jcars ago in the Philosophical Transactions. 



And us the more elevated parts of a country are so much colder 

 than the valiies.owing perhaps to a concurrence of two or three causes, 

 but particularly to the less condensed state of the air on hills, which 

 thence becomes a better conductor of heat, as well as of electricity, 

 and permits it to escape the faster; it is from the water condensed 

 on these cold surfaces of mountains that our common cold springs 

 have their origin ; and which, sliding between 2 of the strata above 

 described, descend till they find or make themselves an outlet, and 

 will in consequence rise to a level with the part of the mountain 

 where they originated. And hence, if by piercing the earth you 

 gain a spring between the 2d and 3d, or 3d and 4-h stratum, it 

 must generally happen, that the water from tiie lowest stratum will 

 rise the highest, if confined in pipes, because it comes originally 

 from a higher part of the country in its vicinity. 



[Young's Nat. Phil. Thomson's Phil. Trans. Editor. 



SECTION V. 



On Cctpillary Tubes and Siphons. 



CAPILLARY tubes are tubes of glass, the interior aperture of 

 which is very narrow, being only half a line, or less, in diameter. 

 The reason of this denomination may be readily perceived. 



These tubes are attended with some singular phenomena, in the 

 explanation of winch, philosophers do not seem to have agreed. 

 Hitherto it has been easier, in this respect, to destroy, than to build 

 up. The principal of these phaenomena are as follow : 



1. It is well known that water, or any other fluid, rises to the 

 same height in two tubes which have a communication with each 

 other; but if one of the branches be capillary, this rule does not 

 hole 1 good: the water in the capillary tube rises above the level of 

 that in the other branch, and the more so, the narrower the 

 capillary tube is. 



It seemed very easy to the first philosophers, who beheld this 1 - 

 phenomenon, to give an explanation of it. They supposed that 

 the air, which presses on the water in the capillary tube, experiences 

 some difficulty in exercising its action, on account of the narrowness 

 of the lube; and that the result must be an elevation of the fluid 

 on that side. 



