I5 2 NATURE STUDY 



finely powdered charcoal to a glow, and then letting it fall into a 

 jar of oxygen. 



The burning of phosphorous gives the brightest light. Phos- 

 phorus must be handled with care. It is best to use a pair of 

 forceps, and cut the piece to be used under water. Dry the water 

 off with blotting paper. It lights easily by friction, and a small 

 piece of burning phosphorus on the hand makes a painful and 

 bad wound. It is poisonous. Handled carefully there is no dan- 

 ger. All small pieces must be picked up and put back into a 

 bottle of water where it is best kept. The phosphorus is burned 

 in the crayon cup as was the sulphur. 



Now questions will arise as to what are the results of the 

 burning in each case. The white smoke in the last is a combina- 

 tion of oxygen and phosphorus, and in each of the other cases an 

 oxide is formed e. </., of carbon, of iron, and of sulphur. Each of 

 the above experiments should be repeated until it is clearly seen just 

 what has taken place. 



These experiments are so interesting to children, that they 

 will not mind having them repeated many times. This is good 

 for giving them clearer notions, better command of handling 

 apparatus, and a familiarity with the facts. 



Carbonic Acid. 



Most of the children have learned that there is carbonic acid 

 in the air; that it comes from the lungs in air breathed out, and 

 that it is made by burning lamps and candles. 



As a good test for the gas will be of great service, it would be 

 better at the very start to explain how lime water is so used. 

 Lime water is readily made by putting some lime into water and 

 allowing it to stand until the excess settles, leaving the solution 

 above clear. Pour off the clear liquid for use. It can be pur- 

 chased ready made at the drug store. 



A small amount of carbonic acid shaken up with the lime 



