198 FOUNTAINS. 



On a small scale a fountain may be constructed in various way 

 The bottom of a wine-bottle may be removed by filing a rather dee 

 notch with the three-cornered file, producing a crack with a pastill 

 and leading it all round ; the notch should be filed several cen 

 metres distant from the bottom, for if too near to the latter, t 

 crack cannot easily be led all round. A glass tube from 50 to 

 long and about 5 mm wide, which has previously been drawn o 

 into a fine point and bent twice at right angles, is passed throu 

 a perforated cork which is fitted into the neck of the bottle (an 

 if necessary fixed with sealing-wax) as shown in fig. 141. T 

 neck of the bottle should be capable of being fixed in the retor 

 stand. Instead of a bottle, a glass funnel may be used, which d 

 not require the bottom to be removed. Or the glass tube ma; 

 be replaced by a long india-rubber tube, one end of which passes 

 over the neck of a funnel, or, if the neck is too wide, over a sh 

 glass tube inserted into the neck by means of a cork, while a gla 

 tube drawn out into a point is inserted into the other end. T 

 funnel may be clamped into the retort-stand and the glass tube 

 held in the hand. To increase the elevation of the jet, it should be 

 directed not vertically upwards but somewhat obliquely, for if tl 

 jet is vertical, the drops which fall back after having reached 

 greatest height impede the upward motion of those drops which a: 

 still ascending, and thus diminish the elevation of the jet. The 

 fork which holds the vessel with water may be placed near the ed 

 of the table and clamped by means of a hand- vice ; the tube descein 

 along the side of the table, and the water is received in a large basi 

 A better way of constructing a fountain will be explained further on 

 when speaking of the siphon. 



In vessels without lateral orifices, as those in figs. 

 114, 115 and 116, the sides are pressed by the liquid 

 with equal force in every direction; hence the vessel 

 does not tend to move in any direction whatsoever. 

 This equilibrium of the pressure on the sides of a vessel 

 is however destroyed, if an aperture at any point in 

 the side allows the liquid to escape, as in fig, 142, 

 where the aperture is on the right-hand side of the 

 vessel. The area of this side will thus be smaller than 

 the area of the left side by the size of the aperture, and 

 the pressure upon the left side is greater than upon the 



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