APPENDIX. 



1. THE teacher should burn a piece of wood or straw 

 in the flame of lamp (Fig. 1), and explain the result. 



2. Burn a piece of charcoal before the class. Notice 

 the dissimilarity between the diamond and charcoal, 

 though chemically the same body. 



3. Provide a tall glass (Fig. 2) and a piece of wire, to 

 the end of which a small bit of wax taper is secured. 

 Put into the glass a few shreds of zinc or iron ; pour 

 upon them a little sulphuric acid diluted with two or 

 three times its bulk of water. Hydrogen gas forms 

 rapidly. Now introduce the lighted taper ; an explo- 

 sion will be heard, and the taper is extinguished. Make 

 the gas in the same manner in a vial (Fig. 3), and show 

 how the gas burns. Remove the cork, and put the taper 

 into the vial. It is instantly extinguished, and the gas 

 ignited, which burns at the mouth of the bottle. Slowly 

 withdrawing the taper, it will be relighted by the burn- 

 ing hydrogen. 



