44 



drawings similar to Figure 32, and indicate where the dial 

 hands stood when you took your readings. 



Record as follows : 



Time of first reading. 



Time of second reading. 



/. Interval during which gas burned. 



Number of gas jets burned. 



Length of time they burned. 



Number of cubic feet of gas consumed by all the jets. 



Number of cubic feet of gas which one jet would con- 

 sume. 



Number of cubic feet of gas one jet would consume in 

 one hour. 



2. Try the same with a mantle burner if you have 

 one. 



Which kind of burner consumes less gas, the ordinary 

 burner or the mantle ? 



What is the cost of gas per 1000 cubic feet in your city ? 



What is the cost to you of a single gas burner per hour 

 at that rate ? 



What is the cost to you of a mantle gas burner per hour 

 at that rate ? 



