THE ELEMENTS OF PLANT FOOD 67 



of the best preservatives for eggs. Fresh eggs immersed 

 in the solution will keep for six months and longer 

 without spoiling. 



Note. Giass has no definite melting point as many solids have. 



If a piece of glass is heated in a flame, it first becomes soft enough 

 to bend, then it may be pulled out into a fine thread, and then on con- 

 tinued application of heat, it turns to a liquid. Likewise, when it is 

 cooled from the liquid state, it goes through all the stages of change 

 back to the solid state. Crystalline substances usually have definite 

 melting points. Substances such as glass that have no definite melting 

 point are called amorphous. 



