MISCIBILITY OF MELTED METALS. 93 



solid may sometimes be thrown out of solution by adding another 

 liquid in which the solid is less easily soluble (such as water). 

 Exactly the same thing occurs with liquids; thus, if a little 

 essential oil of lemon be dissolved in alcohol, and water be then 

 added, the whole becomes milky, because the oil of lemon is 

 thrown out of solution, making its appearance in the form of 

 very small globules, which at first remain suspended in the alcohol 

 and water, like fatty matter in milk, but by and by separate into 

 larger drops of essential oil. Eau de Cologne and many similar 

 perfumes behave in exactly the same way when water is mixed 

 with them, and for the same reason, these perfumes being mostly 

 composed of alcohol, containing certain odorous essential oils dis- 

 solved therein, giving the particular perfumes. Absinthe and 

 various other liqueurs similarly turn milky on mixing with water, 

 because they are spirituous solutions of certain essential oils and 

 similar substances. Very coarse kinds of spirits, such as crude 

 whisky, &c., sometimes become milky when mixed with water, 

 because they contain oily impurities (fusel oil), which are similarly 

 thrown out of solution when the spirit is diluted. 



Expt. 86. Comparative Solubility and Insolubility of Melted 

 Metals in one another. Melt in a crucible an ounce of lead 

 (obtainable at the plumber's), and then throw into the melted 

 mass as much tin ; the latter will immediately melt, and the two 

 fluid metals will mix together, like the alcohol and water in the last 

 experiment, so that no matter how long the melted mixture be 

 kept hot and fluid, the two metals do not separate from one 

 another. 



Repeat this experiment, using zinc instead of tin ; you will now 

 find that the melted zinc and lead will not mix together any more 

 than chloroform and water ; if you stir the mass up well with an 

 iron rod, and then allow it to stand, the zinc will float up to the 

 top, and the lead will sink down to the bottom, forming two 

 layers of liquid metals. A good way to show this is to get a clay 

 tobacco pipe, and plug up the bottom of the bowl with a bit of 

 clay or chalk ; heat the bowl red hot in the flame of a Bunsen 

 burner, and then pour into it the melted metals from the crucible ; 

 keep the tobacco pipe bowl hot for half an hour, and then remove 

 the flame ; when the whole is cold, break away the clay from the 

 ingot of metal. You will find that the lower end is soft, and can 

 be cut easily with a knife, and will mark paper, being in fact lead 

 (containing a small quantity of zinc dissolved, just as the chloro- 

 form retains a little water) ; whilst the upper end is hard, and is 

 zinc containing a little lead (as the water dissolves a little chloro- 

 form). 



