434< Mr. H. Prater on the Anti-viflammable and 



it seems not improbable that these latter may retain their 

 powers longer*. 



As there is little or no difference in the power of these al- 

 kalies, and as the latter is now very considerably cheaper 

 than the former, we give it the decided preference. 



For practical purposes, the subcarbonate of soda will, ex- 

 cept in very particular cases, be found sufficiently anti-inflam- 

 mable; for no great or sudden destruction of property which 

 had been pi-epared by its solution could take place. Fire 

 falling on one of the leaves of a book in a library so prepared, 

 could scarcely be able to extend itself even through the book 

 on which it fell; and certainly could not communicate to 

 other volumes. And whether a child's dress, or the scenes 

 of a theatre so prepared were set on fire, there would be little 

 difficulty in extinguishing it. Although therefore the muriate 

 of ammonia is a more complete anti-inflammable, its great 

 expense compared to subcarbonate of soda is a formidable 

 objection to its ge7ieral use. Papers saturated with it might 

 sometimes be used instead of parchment fj where it was the 

 wish to give the gi-eatest degree of security to the documents 

 or productions. 



In reference to "iioood, muriate of ammonia seems to have 

 no advantage over the subcarbonate of soda. When wood, 

 aliliough cut in the thinnest form^ is prepared by the solution 

 of this alkali, the ignited part will not extend, as we have 

 observed is the case with paper or linen under the same cir- 

 cumstances. The subcarbonate of soda, then, is what we 

 recommend for the preparation of all articles composed of 

 wood. 



But it is fair to consider the grand objection to preparing 

 wood by immersion in the saline solutions (for muriate of 

 ammonia is equally liable to this objection with subcarbonate of 

 soda). The objection alluded to is, that all these saline im- 

 pregnations are completely removed by immersion in water :j:, 



• I have stated in the preceding page, that 1 have specimens of wood, 

 paper, &c., pre|)ared by the inijriate of ammonia in December 1836, which 

 are still quite uninflammable : the same is the case with those prepared 

 by potass and soda at the same time. But it is still possible that these 

 latter may remain uninflammable the longest. I was anxious to know 

 whether the anti-inflammable power seemed to diminish by time; and as 

 it has not hitherto, I hope these experiments will be more worthy public 

 confidence. 



f The reason why parchment is not so inflnn-.mable as paper probably 

 is, on account of its containing more azote. 



\ It need scarcely he stated, that after the saline matter was removed, 

 the wood hi all cases was found to burn with flame, as usual. 



