HOT WATER. 



313 



Fig. 34 



siphon, by taking a piece of lead pipe, say of half an inch 

 bore, and four or five feet long, bending it like a siphon, 

 but one leg a good deal more bent than the other, in order 

 to give the descending water time and space for giving out 

 its heat ; and then, filling this tube with water, and placing 

 one hand on each end to retain it full, immerse the extre- 

 mities in a pot of water over a fire, as represented in the 

 annexed diagram. Supposing the water of 

 a uniform temperature in both legs of the 

 siphon, no circulation would take place ; but 

 supposing it to cool sooner in the long leg 

 a than in the short leg 6, then the equilibri- 

 um would be destroyed, and the water in 

 the long leg a would descend, and draw up 

 water through the short leg b ; and this cir- 

 culation would continue as long as the water 

 c was maintained at a temperature above 

 that of the surrounding atmosphere." 



Mr. Kewley's adaptation of the siphon is one of the 

 simplest and most efficient that has been proposed. In 

 Fig. 35, ace are the two legs of a siphon, through the 

 upper of which the heated water ascends, and by the lower 

 descends. Immediately over the descending bend, a pipe 

 connected with an air-pump is inserted, in order to fill the 

 or remove the air which collects in the superior 

 Instead of the air-pump, a funnel with air-tight. 



pipes, 

 l c mb. 



Fig. 35. 



) 



) I 



