EXPLOSIBILITY OF COAL OILS 337 



composed oil, coal, or wood with this combining portion of atmos- 

 pheric air, and then to apply a lighted match to the mixture. 



Dangerous explosions are thus often produced in common stoves on 

 suddenly decomposing the wood, shavings, or paper used therein for 

 kindling, by throwing red hot coals upon them. The carburetted 

 hydrogen, rising in the form of a dense smoke, becomes commingled 

 with the atmospheric air occupying the chamber of the stove, and on 

 being kindled the whole simultaneously flashes into flame. In "air- 

 tight stoves" these explosions have often proved destructively vio- 

 lent to persons and property. 



Thus there may ensue dangerous explosions even in lighting a fire 

 in a stove ; and most fearful explosions have often taken place in 

 apartments of dwelling houses when about one-fifth part of the space 

 therein becomes occupied by coal gas escaping from leakages of gas- 

 pipes. The difference in the extent of the violence in such cases is 

 simply due to the greatly increased quantity of the explosive gas accu- 

 mulated in large rooms, as compared with the diminutive chambers of 

 comm'on lamps. The extent of the danger to both life and property 

 is thus correspondingly magnified. Even adjacent buildings have thus 

 been damaged and many lives destroyed by such explosions of coal 

 gas. 



There is, therefore, the same danger of explosions in the use of 

 coal gas in houses as in the use of coal oil in lamps where ordinary 

 care and caution are not exercised. Were about five parts of atmos- 

 pheric air mixed in a city gas-works with one j)art of the coal gas, 

 and thus distributed for use, the jet of gas kindled at a burner would 

 communicate the flame to the interior of all the main pipes and gas- 

 holders, and a general simultaneous explosion of all would ensue. 

 The same parallel has been applied to excluding atmospheric air from 

 the chambers of kerosene oil lamps by keeping them filled with oil. 



To compare practically the violence of the explosion of common 

 coal gas with that of the inflammable kerosene coal gas and of naphtha, 

 a small tin vessel of»the capacity of a factory lamp was made for the 

 experiments; the results of which showed that the coal gas was the 

 most readily explosible, the extent of the explosion, however, being 

 only a slight puff from the orifice of the tin vessel. 



The slightness of all the explosions in the experiments that have 

 been recapitulated is ascribable to the small proportion of one-fifth 

 pure oxygen gas contained in the atmospheric air, the remaining four- 

 fifths being composed of incombustible nitrogen. Were pure oxygen 

 substituted for the diluted atmospheric air, the explosions would have 

 been dangerously violent. Indeed, were the atmosphere composed 

 of pure oxygen, the iron grate bars of a furnace would burn more 

 brilliantly than the most combustible fuel placed thereon, and explo- 

 sions and conflagrations would continually occur with irresistible vio- 

 lence. It is owing to the presence of the pure oxygen gas evolved 

 by heating saltpetre, and commingled with the carburetted hydrogen 

 gas evolved from the ignited pine floors and partitions of warehouses, 

 that the most frightful explosions have occurred, which have often 

 blown up great warehouses and destroyed many lives. This fact 

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