PREVENTION AND EXTINGUISHMENT OF FIRES. 161 



one can let an iron pot filled with burning brimstone down into the hold, 

 close the hatches and thus extinguish the fire at once. The chemical action 

 in these cases is the absorption or abstraction of the oxygen from the atmos- 

 phere by the sulphurous acid gas generated by the burning brimstone and 

 the consequent inability of the residue to support the combustion. 



lY. The last suggestion I shall make is the extinguishment of fires by 

 means of vapors or gases generated from the heating or burning of certain 

 materials with which appropriate portions of buildings were coated or 

 otherwise protected previous to their erection. It may seem paradoxical to 

 say that a fire may be made to extinguish itself, but I am not at all certain 

 that it is an impossible thing. Suppose, for instance, that we were to coat 

 the joists under our floors with a mixture of flour of sulphur and glue. When 

 the fire that we will assume to be burning reaches these joists in the confined 

 space between the floor above and the ceiling below, the sulphur will be ig- 

 nited at once, the fumes of sulphurous acid gas given off copiously, the oxy- 

 gen of the air absorbed, and the fire extinguished by its own act ; and so 

 with any other gaseous non-supporter of combustion that we may conceive 

 to be generated by heat. I have never heard of this idea being put into 

 practice, but I see no reason why it should not succeed. 



Steam has also been made to act in this very capacity by being gener- 

 ated, in cases of fire, from vessels of water placed between the outer and 

 inner doors of iron safes and vaults. A remarkable case of this kind was 

 reported in the Journal of Applied Science (Boston), which was in brief as 

 follows : Vessels of water were kept not only between the outer and inner 

 doors, but also inside the vault itself, and when the great fire occurred the 

 result was the most perfect protection of its contents imaginable. When 

 the fire approached this vault the heat at the outer door converted the 

 water within into steam, which had the effect to keep the temperature of 

 the interior so low that not only were the papers deposited within not de- 

 stroyed after several hours' exposure to intense heat, but they were actually 

 unharmed, and the wooden vessels in which the water had been placed were 

 intact. This suggests ideas well worth following out to a greater extent in 

 practice than I am aware of having been done, and I do not doubt that the 

 most important results may be secured by an intelligent and scientific 

 series of experiments in this direction. 



This concludes all I have to say to-night. There is a very small propor- 

 tion of original matter in this paper, bnt if by gathering these facts and 

 suggestions together from a great number and variety of sources and giv- 

 ing them to you in a condensed form, with some attempt at their arrange- 

 ment in proper order and sequence, I have either added anything to your 

 stores of information or furnished you something new and practical to 

 think of, I shall have accomplished all that I had in view in preparing it. 



