94 



SCIENTIFIC A GRICUL TURE. 



water sprinkled on a board, and the sodium will burst into 

 flame of a deep-yellow color. 



(23.) Color some water blue with litmus. Add a drop 

 of acid to turn it red, and then drop a piece of potassium 

 or sodium on the surface. The blue color will be restored 

 as the metal is consumed. 



(24.) Heat in the flame of an alcohol-lamp a piece of 

 magnesium ribbon, and show the brilliancy of its combus- 

 tion. 



(25.) Collect samples of different varieties of soils, and 

 exhibit them to the class. 



(26.) Heat some green leaves or grass on a spatula, me- 

 tallic plate, or small shovel, until nothing is left but the ash. 



(27.) Exhibit specimens of sugar, starch, albumen, or 

 white of egg, etc. 



(28.) Pour some clear lime-water into a wineglass, and 

 by means of a straw or glass tube breathe through the 

 liquid. The milky appearance is caused by the carbon 

 dioxide from the lungs combining with the lime, and form- 

 ing insoluble calcium carbonate. 



(29.) Collect, and show to the class, a few plants with 

 root, stem, and leaves. 



(30.) Pour some water on a lump of unslaked lime. 

 In a few minutes the mass will become hot, combine with 

 a portion of the water, and crumble into powder. 



(31.) Pour some hydrochloric acid on marl, and effer- 

 vescence will take place, caused by the escape of carbon 

 dioxide. 



(32.) Mix a tablespoonful of plaster of Paris with a lit- 

 tle water, and show how it sets, or hardens. 



Exhibit to the class specimens of as many different fer- 

 tilizers as can be obtained. 



