828 Handbook of Nature-Sttidy 



LESSON CCXII 

 Salt 



Leading thought — Salt dissolves in water, and as the water evaporates 

 the salt appears in beautiful crystals. 



Method — Let each pupil, if possible, have a cup and saucer, a square of 

 paper small enough to go into the saucer, some salt and water. Let each 

 pupil take five teaspoonfuls of water and add to this two spoonfrds of salt, 

 stirring the mixture until dissolved. When the water will take no more salt 

 let each pupil write his name and the date on the square of paper, lay it in 

 the saucer, pressing it down beneath the surface. Let some place their 

 saucers in a warm place, others where they may be kept cool, and others in a 

 draft. If it is impossible for each pupil to have a saucer, two or three pupils 

 may be selected to perform the experiments. 



Observations — i. When you pour the salt into the water, what becomes 

 of it? How do you know when the water will hold no more salt? 



2 . After a saucer, filled with the salt water, stands exposed to the air for 

 several days, what becomes of the water? From which saucers did the 

 water evaporate fastest — those in the warm places, or those in the cold? 

 In which did the crystals form first ? 



3 . Which saucers contained the largest crystals — those from which the 

 water evaporated first, or those from which it evaporated more slowly? 



4. Could you see how the crystals began? What is the shape of the 

 perfect salt crystal ? Do the smallest crystals have the same shape as the 

 largest ones ? 



5 . What happens to people who cannot get salt to eat ? 



6. How is dairy salt and table salt obtained? What is rock salt? 

 What are salt licks ? Where are the salt mines found ? Why .is the ocean 

 called "the briny deep ?" 



7. Name and locate the salt lakes. Why are lakes salt? 



LESSON CCXIII 

 How TO Study Minerals 



Many children are naturally interested in 

 stones. I once knew two children, aged seven and 

 five, who could invariably select the boulders and 

 pebbles of metamorphic rock in the region about 

 Ithaca. They also could tell, when the pebbles 

 were broken, which parts were quartz and which 

 mica. They had incidentally asked about one of 



these stones, and I had told them the story of the 



glacial period and how these stones were torn ^ s„g^ crystal. 



away from the mountains in Canada and brought photomicrograph by 



down by ice and dropped in Ithaca. It was a w. a. Bentiey. 



story they liked, and their interest in these granite 

 voyagers was always a delightful element of our walks in the field. 



For the pupils in the elementary grades it seems best to limit the study 

 of minerals to those which make up our granite and common rocks. In 

 order to teach about these minerals well, the teacher should have at least 

 one set of labelled specimens. Such a collection may be obtained from 

 Edward E. Howell, 612 17th St., N. W., Washington, D. C, and also from 



