254 On the Propagation and Growth 



With these materials Dr. Buckner made tlie following ex- 

 periments, which we extract entire: — 



Two drachms of them were reduced to fine powder, and digested 

 in three ounces of distilled water for twenty-four hours. All the 

 three quantities, filtered off from thecharcoal,were uncolored, and left 

 the test paper unchanged. After the evaporation of the water, there 

 remained only a very trifling yellowish residuum, of a saltish taste, 

 which acted somewhat like an alkali, and, besides potash, contained 

 also chlorine. No diflference could be distinguished in this case be- 

 tween a, b, and c. 



The portions of charcoal powder to which water had been ap- 

 plied, were each separately digested in a sand-bath, with three 

 ounces of water, to which a drachm of corrosive lie of potash was 

 added. The liquid filtered from a was almost colorless, and was 

 not the least muddy when saturated with muriatic acid. The liquid 

 from 6 was brownish, and with muriatic acid yielded a flocky dark 

 brown precipitate of humic acid, which, being carefully collected 

 and dried, weighed 0.27 grains. The liquid from c was of a darker 

 color, and, with muriatic acid, yielded 0.45 grains of humic acid. 



Two drachms of each of the three portions of charcoal were re- 

 duced to ashes in the platina crucible. The ashes of a weighed 

 twenty-two grains, and lost, by shaking with distilled water, one 

 grain in weight. The ashes of 6 yiehled only nine grains of ashes, 

 of which only half a grain was dissolved by the water. The ashes 

 of c, on the contrary, weighed thirty-three grains ; apparently be- 

 cause the charcoal powder, while in use for two years, had become 

 fouled with garden mould ; of these thirty-three grains of ashes, two 

 grains were dissolved in water. The constituent parts of the three 

 portions of ashes retained their qualities ; so that in the dissolved 

 parts were fond jiotash, chalk, carbonic acid, sul|»hurjc acid, muriatic 

 acid, and phosphate. The portion indissoluble in water contained 

 chalk, magnesia, traces of oxide of iron, carbonate, sulphuric acid, 

 phosphate and silicic acid. 



If the objection be made, with respect to these three portions of 

 charcoal, that they are not all from the same tree, and might there- 

 fore yield a ditTerent weight of ashes, we may, with probability, sup- 

 pose that this natural difference is very inconsiderai)Ie,as the charcoal 

 was all of fir wood from the neighborhood of Munich, where lime- 

 stone debris is the general understratum of the woods. 



The result is quite decisive and undisputed, that diluted lie of potash 

 scarcely ever dissolves any thing from fresh fir charcoal, and that, on 

 the contrary, charcoal in which plants have grown, being partly 

 changed into humus and this being drawn out by diluted lie of potfsh, 

 amounted in the charcoal 6, after six months' use, to 2.'i5, and in the 

 charcoal c, after being two years in use, to S.75 of 1000. By this it 

 is also |)roved, that charcoal, under the influence of light, air, water, 

 and vegetation, is gradually decotnposed, by losing carbon ; in the 

 place of which hydrogen and oxygen predominate, and concur with 

 the remains of carbonate to form humic acid. 



No less interesting is the further comparison of the ashes of, I 

 •nay say, the virgin charcoal a and the charcoal 6, which had been 



