Manure • 
151 
No. 30 Spirit of hartshorn « * 7 3 
50 Spirit of wine - - 68 
56 Charcoal and spirit of hartshorn - - 63 
49 Spirit of wine - - 63 
3 Spirit- of wine - - 60 
l No manure » -5 7 
9 Bottle No. 2 - - 55 
7 Ditto No. 1 - - - 54. 
12 Bottle No. 1 - - - 48 
5 Spirit of wine «t - - 46 
10 Bottle No. 4 28 
58 Ditto No. 5 - - - 28 
45 Salt ------- 26 
5 3 Gypsum and bottle No. 3 - - 25 
48 Bottle No. 5 - - 17 
1 8 Poor sand - - -11 
Remark I. If this experiment had ascertained no more than 
the solubility of charcoal in water by means of pearl-ash, the time 
employed would not have been lost. Ingenhouz says, it is totally 
insoluble in water. Mr. Davy however knows better— -he observes, 
that hot soap-lees will dissolve some j and that potash and pearl- 
ash have some effect in rendering charcoal soluble in water. ( Lee « 
tures ). Darwin hints at it (240). Dr. Thompson, in his Che- 
mistry, speaks of its probability. It is not improbable. Senebier, 
that pure alkalis dissolve a small quantity ; but not when combin- 
ed with acids. III. 155. In another passaged is insoluble in wa- 
ter, and the alkalies alone have the power of dissolving some parti- 
cles. III. 57. From reading these and other passages, and from 
Mr. Kirwan declaring that to discover the means of rendering 
charcoal soluble in water, was the great desideratum respecting 
manures, I concluded that the result was at least very doubtful— 
but of such complete success, I had no comprehension. It appears 
that mixed in water, and applied in such a loam, the solution, effec- 
tive as a manure, takes place ; as the pearl-ash alone, and the char- 
coal alone, (though both good manures) have an effect far inferior. 
II. That straw steeped in urine should act powerfully is not 
surprising ; but I did not expect that dry straw would have had 
the effect of more than doubling the fertility of the soil. Many re- 
flections relative to the application of dung in a fresh or rotten state, 
