Hydraulics. 51 



leg a pour in at d a quantity of water, which will 

 force the air out of the vessel through the leg b. 

 We then stop both orifices with the finger, as in 

 the common syphon, and immerse the leg b in 

 the vessel e filled with water. The water in the 

 glass will then flow out through the leg a ; and 

 the glass being vacant of air, the water from the 

 vessel e will ascend through the leg 5, and form a 

 most beautiful jet or fountain within the glass 

 vessel. 



The syphon may be disguised in such a man- 

 ner as to produce many entertaining effects. The 

 cup fig. 23, is called Tantalus's cup, from the 

 celebrated fable of Tantalus, who is represented 

 by the ancients as suffering continual thirst, and 

 though he is in the midst of water, is unable to 

 assuage it 



" E'en in the circling Hoods refreshment craves, 

 And pines with thirst amidst a sea of waves; 

 And when the water to his lips applies, 

 Back from his lips the treach'rous water flies.'' 



In the cup there is a figure of Tantalus, and if 

 we pour water into it, so that it shall nearly reach 

 to the lips of the image, the water immediately 

 sinks, and is drawn off again. The truth is, there 

 is a syphon concealed within the image; and 

 when the water is poured into the cup, so as 

 nearly to reach the lips, the fluid is then raised 

 above the bend of the syphon, which of course 

 then begins to act, and the water is drawn off by 

 the longer leg in the manner already described. 



