oct.— dec. 1857.] Mode of protecting Timber from Fire. 1£1 



It is the same method as that employed in patent processes for 

 preserving timber from decay. 



" I am not aware whether Mr. Maugham's process has been sub- 

 mitted to any extensive practical test. Numerous experiments 

 were however instituted on Lieutenant Jackson's process, under 

 the direction of Mr. Bhunel. 



" Specimens of seventeen different kinds of wood were prepared ; 

 corresponding pieces being kept unprepared, and others covered 

 with a coating of paint. Their powers of resisting fire were tested 

 by piling the prepared, unprepared and painted specimens round a 

 perforated sheet iron surface, filled to the top with a bright coke 

 fire. 



" In most cases the prepared wood resisted the action of fire for 

 a longer period, and, when removed from the fire, ceased burning 

 sooner than the unprepared specimens, 



" It was also evident that light porous woods were more effi- 

 ciently protected than those of a denser character. 



" There is no doubt therefore that the combustibility of wood is 

 more or less diminished by either of the above methods of treat- 

 ment, although the protective action must be ascribed to the in- 

 destructible compounds with which the wood is to some extent im- 

 pregnated, far more than to the vapours evolved by the decompo- 

 sition of the small quantities of ammoniacal salts forced into the 

 wood. 



" Although by the impregnating process adopted in the above 

 patents, the preparative solution is believed to be forced into the 

 very centre of the wood, it is essential, if such a result is to be 

 obtained, that the solution should be weak, since it is impossible 

 to force strong saline solutions thoroughly into wood. 



"It is evident that the protective action of the salt cannot, under 

 these circumstances, be very powerful. 



" Were it possible, on the other hand, to employ stronger so- 

 lutions, the expense of the processes would be considerable. 



" The necessity of costly apparatus for impregnating the wood is 

 also a matter of serious moment." 



