APPENDIX. 9I 



if blown out, and the splinter be again thrust into the flask, 

 provided a spark be left, it will burst into flame. If a piece 

 of red-hot charcoal or burning sulphur be lowered into the 

 flask, it will burn with great energy. 



(5.) Place a few scraps of zinc in a deep wineglass, and 

 pour over them a little water. Now pour in a little hydro- 

 chloric or sulphuric acid, and bubbles of hydrogen will rise 

 through the liquid. Bring a lighted match to the mouth of 

 the wineglass, and a slight explosion will ensue, caused by 

 the union of the escaping hydrogen with oxygen of the air. 

 By placing the zinc and acid in a bottle supplied with a 

 cork and glass tube, the hydrogen may be burned as it 

 issues from the tube, or may be collected in a receiver over 

 a pneumatic cistern. Be very careful not to light the escap- 

 ing hydrogen until all the air has been expelled from the 

 bottle, as a mixture of hydrogen with oxygen contained in 

 air unites with an explosion on application of flame. It is 

 always best to surround the bottle with a towel or handker- 

 chief before lighting the hydrogen. An explosion can then 

 produce no bad effects. 



(6.) Remove the cork, and thrust a lighted splinter into 

 the bottle ; a slight explosion will occur, the splinter will be 

 extinguished, and again lighted as it is taken out, while the 

 hydrogen will continue to burn at the mouth of the bottle. 

 A small piece of burning candle lowered into the bottle 

 will show these results to better advantage. 



(7.) Hold a tumbler or other glass vessel over the flame 

 of burning hydrogen, and the water produced will condense 

 on the cool surface. 



(8.) Dissolve some sugar or salt in a tumbler of water. 



(9.) Float a piece of cork on the surface of water, and 

 place on it a small pellet of phosphorus. Now light the 

 phosphorus, and cover it quickly with a glass receiver or 



