WATER FROM FIRE. 137 



ly by holding a cold iron over the flame, at a little distance 

 above it, when we shall find it will be almost immediately 

 covered by a dew formed by the condensation of the vapor 

 into a film of exceedingly minute drops of liquid water. 



And so, when you light a lamp in cold weather, the glass 

 chimney, if put on cold, becomes for a moment bedimmed 

 with a dew produced by the condensation of the aqueous 

 vapor formed by the combustion of the hydrogen. As 

 soon as the glass becomes warm the vapor is no longer 

 condensed, though it continues to be formed as before. 



This phenomenon may be shown 

 in a still more perfect manner by 

 burning a candle for a few minutes 

 under a cold bell glass, and observ- 

 ing the deposition of the water on 

 the interior of the glass, which will 

 sometimes be so abundant as to 

 cause drops to trickle down the 



ATKU FROM FIKE. 



This experiment of condensing water from the products 

 of flame, which any one can easily perform, will succeed 

 better if the iron, or other condensing substance, has some 

 thickness, so as not to become warmed itself too soon, and 

 so cease to condense the vapor; and if it has also a polished 

 surface, as such a surface, by its brightness being dimmed, 

 will show the presence of very small quantities of vapor. 



Sometimes children, when they are writing a letter, and 

 are in haste for the writing to dry, hold it at a distance 

 over the flame of a lamp, not knowing that the hydrogen, 

 which forms a large part of the oil, produces water by its 

 combination with oxygen in the burning, and that this 

 water, in the form of vapor, rises directly to the place 

 where they are holding their writing to dry ! In other 

 words, they hold their paper in a very damp, though in a 



