74 Domestic Science 



Exercise for Student. 



From the information already supplied, make a summary of 

 the general properties of fluids. 



44. Solids may be further distinguished from fluids 

 by the fact that the latter in most cases intermingle 

 freely with one another by the process termed " dif- 

 fusion", irrespectively of their densities. All gases 

 exhibit this property, but some pairs of liquids, such 

 as olive oil and water, do not, for other reasons, mix 

 to any appreciable extent. 



The following experiment should only be performed 

 under the immediate supervision of a teacher. 



EXPERIMENT 24. Dip a long glass tube of narrow 

 bore into a bottle of bromine. (This is a liquid of a 

 very dark red-brown colour, which gives off readily 

 large quantities of dark orange-coloured vapour. This 

 vapour is exceedingly harmful to the membranes of the 

 throat and lungs and must on no account be breathed.) 

 Close the top of the tube with the forefinger and remove 

 the lower end of the tube from the liquid. Let the 

 liquid run out of the tube by slightly releasing the 

 pressure of the finger, till only enough is left to fill 

 about an inch of the tube. Press the finger firmly on 

 the upper end of the tube, cautiously remove the tube 

 from the bottle, and lower it carefully to the bottom 

 of a tall glass cylinder. Remove the finger when the 

 lower end touches the bottom and let the liquid run 

 out. Remove the tube and drop it gently into a large 

 vessel of cold water. Put the stopper into the bottle 

 of bromine. Cover the top of the cylinder with a 

 greased glass plate and put it in a fume-chamber, or, 

 if that be not available, on the sill outside a window. 

 The liquid bromine soon becomes a gas, which is much 



