64 CHEMICAL ACTION. 



Q. Why does not SMOKE acquire its full 

 VELOCITY in a SHORT funnel? 



A. Because the higher smoke ascends 

 in a flue, (provided it be clear and hot) 

 the faster it goes ; (as a stone falls faster 

 and faster the lower it descends) : if, 

 therefore, a funnel be very short, the 

 smoke never acquires its full velocity. 



Q. Does the DKAUGHT of a chimney depend on 

 the SPEED of the SMOKE through the flue? 



A. Yes. The more quickly hot air 

 flies up the chimney, the more quickly 

 cold air will rush towards the fire to 

 supply the place; and, therefore, the 

 longer the flue, the greater the draught. 



Q. Why is the DRAUGHT of a LONG FLUE, 

 GREATER than that of a short one ? 



A. Because the higher smoke ascends, 

 the faster it goes; (as a stone falls faster 

 and faster, the nearer it approaches 

 to the earth) : if, therefore, a funnel be 

 long, the smoke acquires great velocity, 

 and the draught is great. 



Q. If a CHIMNEY be TOO SHORT, and cannot 

 be lengthened, what 'is the best REMEDY to prevent 

 smoking ? 



