76 COMPANION TO TROPICAL READERS 



Expt. 168. Necessity for a Mixed Diet. Collect 

 small samples of different foods, some of which consist 

 principally of carbonaceous matter, and others of which 

 are rich in nitrogen. Put them together so as to form 

 a satisfactory mixture of heat-giving and flesh-forming 

 foods, e.g. rice and peas, salt fish and akee. 



Expt. 169. Milk a Mixed Food. 



(a) Albumen. Pour some lime-juice on milk, and ob- 

 serve that the albumen coagulates in the form of curd. 



(b) Fat. This may be observed by allowing a glass 

 of milk to stand for some time. 



(c) Sugar is contained in the whey. Evaporate the 

 whey on an enamel dish over the fire; it will soon char. 



(d) Ash. Continue burning, and the residue will be 

 mineral matter. 



WATER I and II 



(See Tropical Readers, Book II, pp. 153-160.) 



Expt. 170. Properties of Water. Examine some 

 water and observe that 



(a) It is a clear, tasteless, inodorous liquid. 



(b) It is colourless in small quantities, but in large 

 quantities it has a bluish tint. 



Expt. 171. Three States of Water. Get a lump of 

 ice; allow it to melt; boil the water so formed until it 

 has all passed off as steam. 



Expt. 172. Water dissolves Solids. Put some com- 

 mon salt or some magnesium sulphate in water, stir until 

 dissolved; taste the liquid to prove the presence of the 

 substances in solution. 



Expt. 173. Difference in Rain-, River-, and Sea- 

 water. Evaporate equal quantities of rain-water, river- 



