278 Domestic Science 



EXPERIMENT 127. Suppose that we wish to find 

 out if marble is at all soluble in water. Put about 1 g. 

 of marble in a beaker containing at least 100 c.c. of 

 distilled water. Heat the water to boiling-point and 

 continue the heating for about five minutes after, the 

 water starts boiling. Filter, if suspended particles 

 render this operation necessary, and put six drops of 

 the filtrate, or, if filtration be not resorted to, of the 

 clear liquid above the marble, into a watch-glass and 

 evaporate to dryness. Similarly treat six drops of 

 the distilled water used in making the solution and 

 compare the quantities of residue left in the two cases. 

 Should no difference in amount be perceptible, the 

 marble is insoluble, and vice versa. 



Test the solubility of each of the following sub- 

 stances, and group them according as your results 

 indicate them to be readily soluble, slightly soluble, 

 or insoluble : 



Plaster of Paris, red lead, copper oxide, slaked lime, 

 bronze (a penny will do for this, if cleaned before use), 

 powdered glass, calcium chloride, mustard, and cocoa. 



193. Liquids resemble gases and solids in exhibit- 

 ing varying degrees of solubility in water. Some, such 

 as alcohol, dissolve in all proportions and are said to 

 be perfectly miscible with water ; others, of which 

 ether is ah example, will dissolve to a limited extent, 

 and are termed partially miscible ; while many liquids, 

 especially those of a fatty nature, such as paraffin and 

 olive oils, are almost insoluble in water and are said to 

 be immiscible with that liquid. 



EXPERIMENT 128. Into each of three 200 c.c. 

 graduated cylinders, provided with close-fitting stoppers, 

 pour 100 c.c. of water. To the water in the first add 

 20 c.c. of alcohol (spirits of wine), to that in the second 



