316 MOLECULAR PHENOMENA IN GASES. 



across the upper end of a glass or paper tube (the latte 

 can be made by rolling a piece of paper over a glas 

 tube and pasting the edges upon one another), fron 

 0*5 to l m< 5 long and 8 or 10 mm in diameter, in such ; 

 direction that the angle between the tubes is a littL 

 more acute than the angle between them in fig. 205, ; 

 cork, small enough to fall through the longer tube easih 

 when it is held vertically, will, if placed inside th 

 lower end, rush up the long tube towards the end upoi 

 which the air is blown, and will dart away in a curve. 



The liquid and the cork are driven by the externa 

 pressure through the tube towards the spot where th 

 issuing gaseous jet has a pressure less than the atrnos 

 pheric pressure. 



A current of steam exhibits more strongly sue! 

 phenomena of suction, than one of air, as will be show: 

 in the chapter on HEAT. 



31. Molecular phenomena in gases. Condensatio 

 upon surfaces. Absorption. Diffusion. Gaseor 

 bodies manifest adhesion upon solid bodies ; they ai 

 attracted and held so strongly by solid surface; 

 that a kind of condensation takes place. The large 

 the surface of a solid body, the greater is the quantit 

 of gas which may be condensed by it ; hence poroi 

 bodies are capable of condensing so much, that the 

 appear to absorb it. This kind of attraction is n( 

 manifested to the same extent by all solid and gaseot 

 bodies. It is especially remarkable between carbon 

 acid and charcoal. A piece of charcoal absorbs 

 volume of carbonic acid, many times larger than itsel 

 If a small glass vessel full of carbonic acid be invert* 

 in mercury, so that its mouth dips below the surfac 



