Scientific Lectures. 217 



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This principle is not limited to small machines to be earned on 



one's back, but can be applied to engines of large size. 



Even steam extinguishes combustion. In some of the oil refineries 

 an arrangement is made by which any one of the apartments can 

 be closed, and a jet of steam forced into it, rendering combustion 

 impossible. 



It has been suggested that liquified carbonic acid should be carried 

 in ships. A pressure of 600 pounds to the square inch condenses it 

 into a liquid, a gallon of which will fill fifty cubic feet upon the 

 removal of the pressure. A few barrels of this, if there should be a 

 fire under the deck, would fill the whole interior of the vessel, and 

 the fire would necessarily be extinguished. 



It has been proposed, and I believe a charter has been obtained 

 from the Legislature, for a company to lay pipes in the streets to 

 supply carbonic acid to put out fires. The idea is plausible ; but we 

 must remember that this gas not only puts out fires but puts out 

 lives ; and it becomes a question whether we shall have a death-deal- 

 ing agent delivered at our doors, as well as a fire extinguisher. The 

 street gas smells badly, notifying us of a leak ; and it burns, so that 

 a leak is readily found. But carbonic acid has no smell, and does not 

 burn. A leak occurring in the neighborhood, even were the pipe 

 not brought into the house, the gas might find its way into our cellars, 

 and some unfortunate member of the family might be suffocated by 

 it. It never would be safe to bring carbonic acid through the streets. 

 It is better to have our fires, to lose our two millions of property every 

 year, than to have our lives destroyed from the leakage of this insidi- 

 ous poison. 



Rendering Fabrics Non-inflammable. 



Various methods are known by which the inflammability of light 

 materials, especially cotton and linen fabrics, used for ladies' dresses, and 

 for window curtains, may be greatly diminished. Accidents are con- 

 stantly occurring from the ignition of such fabrics, lace curtains from 

 gas burners, but more particularly ladies' dresses. Most painful and 

 fatal accidents have occurred in theaters from the foot-lights. In one 

 instance the flames were communicated from one to another till the 

 dreadful spectacle was presented of eight ballet dancers wrapped in 

 deadly flames. A few years since, attention was specially called to 

 this danger, I believe, by the death of a princess, by the ignition of 

 her light muslin dress by a match carelessly dropped on the floor, on 

 which she stepped. Queen Yictoria requested Prof. Graham, Master 



