C 'A PILLAR Y A TTRA CTION. 



29 



tint by iodine, and this enables us easily to observe 

 drops of any one of these liquids on the other. 

 In the three bottles now before you the clear 



FIG. 9 



liquid is sulphate of zinc in one bottle it nas a 

 density less than, in another equal to, and in the 

 third greater than, the density of the sulphide 



