HEAT CONDUCTION. 



we are less likely to have to explain to beholders 

 why the water did the opposite of what we had 

 prophesied if we keep the upper surface smooth 

 and bright. 



Let the copper dish, supported on a con- 

 venient frame, be heated red-hot, and then 

 let a few drops of cold water be carefully 

 poured upon it. Instead of flashing instan- 

 taneously into steam, the water will rest on 

 the dish in the form of a flattened globule or 



FIG. 36.-WATER IN SPHEROIDAL STATE ON RED-HOT METAL 



spheroid, from which this state of matter has 

 been called the spheroidal state. 



Sometimes the globule is horizontally quite 

 round, sometimes of the indented formation 

 shown at B, sometimes its form varies, and 

 sometimes it spins slowly round. 



Why does the water, so close to the exces- 

 sively hot dish, and surrounded by the rising 

 flame from a large Bunsen, not flash into steam 

 at once, but rest in its place for many minutes 

 before it has slowly dried away ? 



153 



