486 NATURE STUDY. 



CLOUDS. 



41 We have all seen the clouds. 

 Some of us have seen pictures in the clouds. 

 Jamie saw a little golden cloud. 

 The sun shone on the cloud, and made it golden. 

 John saw a little silvery cloud. 

 The moon shone on the cloud, and made it silvery. 

 A little star shone through this cloud. 



Winifred and Albert have seen clouds that look like mountains. 

 The clouds have work to do. 



They wear their dark dresses when they do their work. 

 They send us rain and snow. 

 The clouds are bunches of water dust." 



WATER DUST, FROST, ICE, SNOW. 



Preparation. Review by experiment the conditions 

 necessary for making water dust : water ; some heat to 

 evaporate it ; some cold to condense it. Show how much 

 more rapidly it is formed when the vapor is shut in so that 

 it cannot scatter through the air, and when the air is there- 

 fore full of vapor. This can be shown by placing a bottle 

 of ice-water on a cork or block of wood in a saucer contain- 

 ing a little warm water, and inverting over the saucer and 

 bottle, a glass jar, or tin can. 



FROST. 



Formation. Use the same apparatus as is described 

 above. Use a wide-mouthed bottle, such as a quinine bot- 

 tle, and fill with a mixture of finely pounded ice and salt, 

 about one-quarter salt and three-quarters ice. Good results 

 can be obtained with a half-pound baking-powder can 

 (with the paper removed from part of it), to contain ice and 

 salt, and, inverted over it, a two-quart tin fruit- or coffee- 

 can (with a nail-hole in it). Show children that the ice 

 is used to make the bottle or can cool, and the salt to help 



