20 THE NATURE-STUDY REVIEW i 3 : i-jan., 1907 



things in nature best worth knowing" — is liable to put the teacher 

 on the wrong track. It has been part of my duty to criticize many 

 a nature-study lesson; what I have seen has convinced me that the 

 proper subjects for nature-studies are not the things best worth 

 knowing by adults but the things best worth doing and thinking 

 about by children. Dr. Hodge has declared elsewhere that we need 

 the spirit of genuine research as we need life, that it is "the breath 

 of life of education." If there is any genuine research by pupils 

 in his paper, "Nature-Study Work with Insects" — I should be glad 

 to have it pointed out. 



Normal School, John Dearness. 



London, Ontario. 



THE FOUNDATIONS OF CHEMISTRY IN NATURE-STUDY 



II. Oxidation 



A day or two before beginning the following experiments, some 

 lime-water should be prepared. This may be done by shaking a 

 few teaspoonfuls of fresh water-slacked lime in a quart bottle nearly 

 full of water. When the undissolved residue has settled, the clear 

 solution of slaked lime (lime-water) may be poured off as needed. 

 Get some wood charcoal from a stove, or prepare some by charring 

 a stick. Bend the end of a common brass wire, about 10 inches 

 long, about a small piece of the charcoal, closely enough to prevent 

 the charcoal from falling out but not to conceal it from sight. Leave 

 the rest of the wire for a handle. 



Shake together in a test-tube a few crystals of chlorate of pot- 

 ash and a less bulk of black oxide of manganese. 



Try a test stick (a hardwood toothpick is just the thing), first 

 merely glowing at the end, then burning with a flame, in the mouth 

 of the test-tube. Note the results. 



Heat the mixture with a spirit-lamp till a glowing stick will burst 

 into flame when held in the mouth of the tube. Keep the tube 

 loosely closed with the thumb between the tests. 



The pupils may be told that this gas in which the stick will 

 burn so much more readily than in air is called oxygen and that it is 

 a simple substance. 



Add a little chlorate of potash to the mixture, insert the mouth 

 of the test-tube into the neck of a small wide-mouth bottle held with 

 the mouth turned obliquely downward, and apply heat again till a 

 glowing stick will promptly burst into flame when held in the 



