152 PREVENTION AND EXTINGUISHMENT OF FIRES. 



At this point I desire to digress briefly, to point out the advantages 

 which would be possessed bj wood rendered incombustible over those ma- 

 terials ordinarily used by persons undertaking to construct fire-proof build- 

 ings, viz : stone or iron. 



1. Such timbers would be more easily and readily transported, worked, 

 handled and fitted, than either stone or iron. 



2. They would not crumble or disintegrate under exposure to heat, as 

 did the granites, sandstones and marbles of Chicago and Boston. 



3. They would not exj)and under similar exposure and overthrow the 

 buildings they were intended to support, as it is the well known tendency 

 of iron columns, beams and joist. 



4. They would not at a heat of from 1200° to 1500° P. become soft, as is 

 the case with cast iron when red hot, and liable to yield to a superimposed 

 pressure which it would really support when cold. 



5. They would not be cracked or fractured by the application of water 

 to them when hot, as is the fact concerning both stone and iron. 



6. They would not under any circumstances tend to ignite spontane- 

 ously themselves nor produce the ignition of adjoining inflammable mater- 

 ials, as is believed by scientific men be the case with iron when oxidizing in 

 contact with wood or other combustible substances. 



Under none of the circumstances named above will wood which has 

 been rendered fully fire-proof be unfavorably afl'ected, but on the contrary 

 it will resist all of the effects of heat upon stone and iron just given, be- 

 sides some others of minor importance. 



IsTumerous attempts have been made to achieve this desirable result, but 

 a& yet no certain success has been reached. Among the various substances 

 suggested for the purpose are sulphate of iron or copperas, sulphate of lime 

 or gypsum, and various other salts, mostly of the alkalies, with which it is 

 proposed to fill the pores of the wood. That success may be reached in 

 this way there is no reasonable doubt, for even dry gunpowder itself may 

 be prevented from burning by separating its particles by means of almost 

 any incombustible material pulverized and mixed with it, such as earth, 

 sand, powdered glass, etc.; but the difficulty seems to be to find some means 

 of introducing the protecting salts into the wood less expensive and elabo- 

 rate than any yet proposed. 



The present methods are to first prepare the wood by kiln drying, to de- 

 prive it of its moisture and volatile oils, then by great pressure force the 

 preservative fluids into the open pores of the wood ; or, to exhaust the air, 

 moisture, etc.,2w vacuo and then introduce the salts by atmospheric pressure 

 alone. Still another plan is to displace the fluids in the lumber by colum- 

 nar pressure, as an apothecary displaces one fluid with another in prepar- 

 ing his tinctures ; all of which methods are expensive and troublesome. 



An English clergyman, by soaking the wood in a solution of tungstate 

 of soda, succeeded in rendering it completely impervious to fire. The fol- 

 lowing were some of his experiments : " Two small pyramids of sticks 



