Note 5 — Chapter XIV · OXYGEN.

Dangerous Explosibility of Mixtures of Oxygen and Hydrogen.—At this point a warning should not be omitted, for mixtures of oxygen and hydrogen gas, whether produced purposely or by accident, are capable of very dangerous explosions. Even a soap bubble, inflated with the mixed gases, and then lighted with a torch, explodes with tremendous violence and a loud report. This result is all the more wonderful when the extreme thinness and weakness of the filmy confining envelope is considered. Such explosions are in entire harmony with the various statements already made. For when the two gases combine, the intense heat then generated gives rise to a momentary but enormous expansion of the vapor of water produced by the combustion. The greatly expanded vapor immediately strikes the air a sharp and violent blow. In another instant however the vapor suddenly cools and condenses to an exceedingly minute drop of liquid water. Immediately upon this effect, the air that was previously forced outward immediately falls into the vacancy left, and now a second blow results. It is these two violent shocks the one following the other in almost instantaneous succession, that produce the report; and to the same causes must be referred the terribly destructive results of the accidental explosion of considerable quantities of the mixed gases. It is plain therefore that all contrivances, destined to employ these gases in close proximity, must be handled with great caution when ready for use.