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That particles of carbon may make a colorless flame bright 

 may be shown by sprinkling lamp black or powdered charcoal in an 

 alcohol flame. On the other hand if with a glass tube drawn out to a fne 

 point, or with a blow pipe air is blown well into a candle flame, the whole 

 of the flame will become blue, no longer giving out much light. 



The better supply of air makes a more prompt combustion of all 

 gases and carbon, but with the result of less illumination. 



If the supply of air to the candle flame is interfered with it smokes, 

 much of the carbon and gases escaping unconsumed. 



The smoking lamp, the smoking fire means a poor combustion. In 

 each case the smoke may be reduced by a better supply of air. Questions 

 may be proposed which will explain the advantage of lamp chimneys, 

 smoke stacks, tall chimnej^s and other devises for causing better com- 

 bustion. 



Cooling the candle flame by thrusting into it a cold substance, such 

 as a bar of metal, causes it to smoke. Carboa burns only at a high tem- 

 perature, and in this case much heat is lost to the cold subtance. 



Those substances which contain much carbon, such as turpentine, 

 camphor and sealing wax may be made to give out a very black smoke. 

 The carbon may be caught as soot or lamp black, which subsequently 

 can be burned. 



In general we depend upon the carbon for the light in the illuminat- 

 ing flame, but in the calcium light a very hot flame is used to heat a 

 piece of lime (calcium oxide) to a white heat, which gives out 

 the bright light. In the stereopticon, oxygen aad illuminating gas is 

 used to heat the lime. In the class room a blow pipe and an alcohol 

 flame can be made to give a bright glow to a piece of lime sufficient 

 to illustrate this point. In the experiment alreadv given of burning the 

 magnesium ribbon, it is the white dust, the magnesium oxide resulting 

 from the combustion that gives the light. 



The foregoing should be broken up into many lessons. These will 

 suggest many others. The applications of what has been given are very 

 numerous, and if well followed out will make clear many things in every 

 day's experience with lights and fires. 



rietals. 



The metals may be made the subjects of a large number of les- 

 sons. The lessons may be extended to the uses of the metals, such as 

 found in the house, in the car, in the shop, and wherever the pupil may 

 discover them. Following these, there may be in some of the grades a 

 limited number of lessons on the ores of some of the metals, the loca- 

 tion of mines, methods of mining and extracting the metals. In any 

 grade the study of the common metals, their properties, and uses may 

 be taken up. 



Provide for work with the metals: a file, a harnmer, a thick piece of 



