THE ATMOSPHERE. 



of the atmosphere, or has it not, a relation to life and 

 health ? 



3. What vital process in the animal kingdom is con- 

 ducted by the atmosphere 1 



4. How many times do persons commonly respire in a 

 minute ? 



5. About how much air is received into the lungs at 

 each inhalation 1 



6. Which ingredient in the atmosphere is most abun- 

 dant, oxigen or nitrogen ? 



7. Which of the two essential ingredients in common 

 air is most active ? 



8. If a person be deprived of oxigen, how will he be 

 affected ? 



9. Which substance is essential to combustion, oxigen, 

 or nitrogen ? 



10. Does carbonic acid promote or destroy combus- 

 tion ? 



11. Why does the bellows hasten combustion ? 



12. Why is fire preserved by covering it with ashes ? 



13. Which ingredient in the atmosphere conducts the 

 process of fermentation? 



14. How many changes does vegetable matter undergo 

 by the process of fermentation ? 



15. What substance is produced by the first change, 

 acid or sugar ? 



16. During which change is alcohol formed, the second 

 or fourth? 



17. In what does fermentation, if continued, always 

 result ? 



18. Which change is most rapid, the second or third 1 



19. How should liquids undergoing the second change 

 be treated, excluded from the air, or exposed to it ? 



20. When a liquid is undergoing the third change, or 

 forming into vinegar, does the fermentation need retard- 

 ing or hastening ? should it be excluded from the air or 

 exposed to it ? frequently moved or remain at rest 1 



21. Which portion of the air has the agency in cor- 

 roding metals, and producing rust, also paints, oxigen, 

 or nitrogen ? 



22. Which metal most readily combines with oxigen, 

 gold or iron ? 



