16 LABORATORY LESSONS IN GENERAL SCIENCE 



9. Close the lips tight, take a deep breath, hold the 

 nostrils tight shut with thumb and finger, and note the 

 length of time you can refrain from exhaling. 



10. Expel the air from the lungs as fully as possible, 

 and note how long you can keep from inhaling. Account 

 for its being a shorter period than for exhaling. 



What would be the result of shutting off from the lungs 

 all air supply for even so short a time as 10 or 15 minutes? 

 What is the real nature of death by drowning? 



11. State so far as known to you the steps taken to re- 

 suscitate (restore to life) a drowned person, together with 

 the purpose of each step. What is meant by asphyxiation 

 (as-fik-si-a'shun) ? 



THE HUMAN BODY AS AN ENGINE 



1. From a general knowledge of steam engines, state (a) 

 the purpose of burning fuel in the fire box; (6) the need of 

 a draft. 



2. What is true of the relative amount of fuel needed 

 when the engine is (a) working full capacity, and when 

 more or less inactive ; (6) well protected from the cold, and 

 when left exposed ? By what means is water changed into 

 steam? What then is there in the steam that does the 

 work for which the engine is employed ? 



3. What will be the effect (a) if the fuel supply is exhausted ; 

 (6) if the draft is shut off for any considerable time ? 



What is true of the power of the steam engine when there 

 is insufficient heat? What is the significance of escaping 

 steam when a locomotive is not at work? 



