Anti-dry-rot Poxvers of Suhcarbonate of Soda, ^-c. 4-33 



slon, and then put into the flame of a candle, they turn black 

 but do not take fire, and on being removed from the candle 

 they do not continue to keep alight like tinder, ignited as it 

 were, but without flame. Solution of muriate of tin possesses 

 an anti-inflammable property to the same degree. These there- 

 fore will stand first on the list *. 



It is worthy of remark, that neither calico, linen, paper, nor 

 wood seem to lose their anti-inflammable property by pro- 

 cess of time ; at least I have some specimens in my possession, 

 prepared in December 1836, which are still as inflammable 

 as at first. This seems in accordance with Prof. Faraday's 

 experiments, who did not find the muriate of ammonia to 

 be volatilizable at the common temperatures of the atmo- 

 sphere f. 



But as neither the muriate of tin nor the muriate of am- 

 monia is sufficiently cheap for extensive use, we are now to 

 examine the fixed alkalies in reference to the property under 

 consideration. 



The subcarbonates of potass or soda seem sufficiently effi- 

 cacious, though not to an equal degree with the salts first men- 

 tioned. There is little or no difference in the efficacy of either 

 of these alkalies. They both prevent viflammability : but 

 neither of them prevents ignition if we may so speak, that is to 

 say, when paper or linen is prepared by them and held in 

 the flame of a candle and then removed, no fame \s communi- 

 cated, but the ignited part or spark continues to spread 

 sloxaly until the whole of the material is consumed. And this 

 it does, whether the substance be held in one direction, or 

 another ; though of course the ignited margin extends most 

 quickly when it is held in such a position that it can rise 

 upward. It is to be obsei-ved, that whether calico, linen or 

 paper be soaked twenty-four hours or a weekij;, in solutions 

 of the alkaline subcarbonates, makes little or no difference in 

 reference to this power of ignition. It is hence obvious, that 

 the muriates of tin and ammonia are more decidedly anti- 

 inflammables than the subcarbonates of potass or soda ; but 



[* Mr. Prater does not mention borax, which is one of the most ef- 

 fectual jjreservatives of muslin and similar fabrics from inflammation and 

 rapid combustion. — Edit.] 



\ Phil. Trans., 1830. Some of the paper prepared by muriate of am- 

 monia was kept by the author at a heat as great as the hand could bear 

 (probably from 120° to 140°) for an hour, without being rendered in the 

 least more inflammable. 



J But the texture is injured by such long immersion, though not ren- 

 dered more anti-inflammable, as many experiments have decided. 



Phil. Ma". S. 3. Vol. It. No. 91. June 1839. 2 F 



