252. Why should persons whose clothes take fire, throw themselves down?
Because flame spreads most rapidly in an upward direction.
253. Why should persons whose clothes are on fire roll slowly about when they are down?
Because they thereby press out the fire.
254. Why does pressing a flame or a spark put it out?
Because it prevents the contact of the flame or spark with the oxygen of the air.
Extinguishers put out the flame of candles in the same manner. A person dies from "suffocation" through the absence of oxygen; and it is literally practicable to "suffocate" a fire.
255. Why does the wick turn black as it burns?
Because it consists principally of carbon.
256. Why, when the point of the wick turns out and meets the air, does it exhibit a bright spark?