232 



GENERAL SCIENCE 



and a yellowish (and perhaps reddish) precipitate forms. Cane sugar 

 does not give this result with the Fehling solution, although some few 

 other less common sugars do. 



Exercises 



1. Name various grains having extensive use as foodstuffs. What others 

 are less commonly used? 



2. Name the two food elements constituting the larger part of the grains. 



Wherein does the food value of wheat exceed that of an equal weight of 

 corn? 



FIG. 76. Boiling maple sap. The old way of making maple syrup. 



3. Name several foods other than the grains that are rich in starch. What 

 is the chemical test (a) for starch; (b) for gluten; (c) for sugar? 



4. What purpose is served by the gluten of wheat flour in the making of 

 loaves of bread? Wherein lies the difficulty experienced in making 

 bread from corn or rice flour? 



6. What is the purpose of yeast in bread making? What advantage in its 

 use over baking powder? Why is the flour for bread moistened with 

 water, and the dough " raised" in a warm place? What causes sour 

 bread? 



6. What is the purpose of kneading several times the dough from which 

 bread is to be made? Name four important ends accomplished in the 

 baking of a loaf of bread. 



