PREVENTION AND EXTINGUISHMENT OF FIRES, 155 



place them, within the reach of most poor men desiring to build cottages 

 for themselves and their families, are much more ready attainable than has 

 hitherto been supposed. 



lY. I deem it perfectly proper and within the legitimate scope of this 

 article to speak of the prevention of fires by the treatment of our inflam- 

 mable bedding, curtains, and even the clothing of our women and children 

 with certain chemical preparations, which, while they do not ordinarily in- 

 jure these fabrics, will prevent their readily taking fire, and thus additionally 

 endangering our dwellings and other buildings, and even the lives of our- 

 selves and families. 



Among the chemicals whose use is suggested in rendering such articles 

 fire-proof, are common salt, which is highly recommended as being quite 

 effectual and less liable to injure the fabrics than many of the others, alum, 

 borax, tungstate of soda, chloride of zinc, a mixture of tungstate of soda (25 

 parts), phosphate of soda (3 or 4 parts), and water (100 parts) ; a mixture 

 of sulphate of ammonia and gypsum; a mixture of alum (3 parts), copperas 

 (1 part), etc. A incombustible starch has also been suggested, composed 

 of a mixture of phosphate of ammonia-magnesia and tungstate of soda in 

 starch ; another composed of the cystals resulting from a combination of 

 ■chloride of calcium and acetate of lime mixed with starch ; and still another 

 prepared by mixing an acid solution of the chloride of zinc with starch. 

 These starches applied to the fabrics in the ordinary way have been found 

 very effectual protectors against fire in many instances. 



For protecting the scenery of theaters, curtains and other movable hang- 

 ings, a coating of water glass, with a little glycerine added to prevent its 

 cracking and breaking off, has been highly spoken of. 



Y. I now come to the consideration of the prevention of fires by me- 

 chanical obstructions. These are mainly of service in hindering and pre- 

 venting the spread of the flames from building to building, and consist 

 chiefly of fire walls and metal roofs, cornices, shutters, etc. Yery little can be 

 said about the first, except that they are usually entirely too low to be of 

 much service, my opinion being that no fire wall less than six feet high 

 will afford any reliable and certain protection to an adjoining building. 

 Mr. Yesey recommends in addition to the ordinary fire walls between build- 

 ings, the carrying up of walls, between blocks of buildings separated by 

 alleys, to a considerable height above any of the buildings, for the purpose 

 of preventing the spread of conflagrations across such alleys or narrow 

 streets. 



Metallic roofs, instead of lying directly — i. e., flat upon the sheathing be- 

 neath, should rest upon it only at as remote points as their proper support 

 requires, leaving elsewhere a space of at least two inches between them, to 

 prevent the heat of fires passing through the metal and igniting the wood 

 beneath. I was very much surprised a few years, since to observe how 

 readily I could ignite a pine board, such as is ordinarily used for sheathing 

 by burning a handful of shavings upon a piece of tin roofing placed upon 



