Substances. 125 



TEN LESSONS ON COMMON OBJECTS. 

 SUBSTANCES. 

 I. Charcoal. 



Each pupil is supplied with a small piece. By questions 

 obtain the descriptive terms black, light, porous, woody struct- 

 ure, soft (it rubs off on the hands), tasteless, odorless, etc. 



Questions to find out how it is made. Propose to the 

 pupils to make some by ordinary charring in the stove at 

 home. Try different kinds of wood pine, poplar, oak, hem- 

 lock, walnut, etc. to see which kinds make the hardest, and 

 which the softest. 



This will disclose the fact that some wood makes excellent 

 charcoal (as willow), while another makes a poor quality 

 (as pine). 



With older pupils observation may go farther, and show 

 that such woods as pine, hemlock, etc., which contain much 

 resin, do not make good charcoal, while oak, willow, etc., 

 having less resin, make far better charcoal. 



Ask for the uses of charcoal, i.e., fires, filters, medicines, 

 artists' work, etc. 



Explain (unless the work is carried on in the vicinity) 

 how charcoal is made for the market ; how charcoal-burning 

 is a great industry in some parts of the world where timber 

 is abundant. With young children ignore the chemical 

 properties. 



II. Sulphur. 



Pieces of ordinary brimstone are best for the opening 

 lesson. What is its color? Its taste and smell? Will it 

 scratch iron ? Glass ? Wood ? (to test hardness) Will it 

 melt ? Burn ? Dissolve in water ? Show 'the class some 

 flowers of sulphur. Melt some in an old spoon. Let it take 

 fire. How does it smell ? Why do matches smell so ? 



Dissolve a little sulphur-flowers in a few drops of carbon 

 bisulphide ; let it evaporate slowly, and beautiful crystals 

 of sulphur will form. These look like sets taken from 



