180 CALCAREOUS MANURES— APPENDIX 



by most persons as secondary in force to another, viz: the dropping of the 

 leaves, and especially of the numerous black-gum trees, and their berries, 

 at that season, on the sv/amps and in the streams. Of course such is the 

 source of the coloring matter; but it would produce no notable or abiding 

 effect, but for the want of lime both in the soil and in the water. The ex- 

 tensive tide swamps on the creeks of James river, are covered with a dense 

 growth of trees, of which a large proportion are black-gums. Yet in the 

 numerous rills trickling or oozing out of these soils, after some days of 

 low tides, I have never observed the water to be dark, or in the least dis- 

 colored. Yet the soil of these tide swamps is as much of vegetable forma- 

 tion as any capable of bearing trees, and is believed to be more so than the 

 swamp lands of Blackwater river and its tributaries. Therefore it is not 

 the abundance of dead vegetable matter in a soil, nor the quantity or kind 

 of leaves furnished by the trees growing on it, wliich alone or together 

 produce colored waters. The earthy portion of the soil of these tide 

 marshes and swamps, small as is its amount, is not acid, but neutral, and 

 the lime contained serves to prevent the water remaining discolored. 



Yet this is not always the case on tide swamps. The waters of Poco- 

 moke river, flowing into the Chesapeake, are black, which I presume is 

 owing to the deficiency of lime in the water and in the surface soil of the 

 lands from which the waters flow. 



The great Dismal Swamp of Virginia and its lake, and the still more ex- 

 tensive swamps and lakes of North Carolina, all present black waters, and 

 which may all be accounted for by the reasons here given. 



Neither is it necessary that marl beds should be wanting to produce the 

 effect of black waters. It is only necessary that the marl (no matter how 

 abundant) should be so far below the surface as not to affect the overflow- 

 ing waters, and that the soil of the higher lands should be generally of acid 

 quality. Such are the lands on Blackwater river and its tributaries. And 

 though marl was scarcely known any where there twenty years ago, it is 

 now known to be abundant, and generally to be found, though almost al- 

 ways a few feet below the surface of the low lands. 



Many persons who would concur with me as to the premises and results, 

 would yet ascribe the coloring of certain waters to the more level surface of 

 the land, and the more sluggish and stagnant state of the waters ; and would 

 suppose the absence of coloring matter in the waters of the upper country to 

 be caused by the rapidity of the descent and of tiie passage of the streams. 

 This would be a correct view, if the matter in question were the degreeof 

 intensity of color, instead of the existence or entire absence of color. It is 

 true, and obvious, that if the colored waters which now creep and stagnate 

 over the level lands below the falls, had as rapid a descent and free discharge 

 as the mountain torrents, their color could not be made deeper by the long 

 infusion of the leaves, nor by evaporation of still waters. But though the color 

 would be much more pale, its existence would not be the less certain. The 

 source of coloring matter, the soaking of dead leaves, &c., in rain water, is as 

 abundant in the upper as in the lower country; and the more rapid discharge 

 of the waters, if no other cause of clearing them operated, would not pre- 

 vent their becoming and remaining colored, as generally, and, however more 

 pale in tint, would be seen as obviously, as in the most level lands. But this 

 is not all. Though there is almost no level land, and therefore no swamps 

 in the hilly or still less in the mountain region, there are mill-ponds in the 

 lower hilly country, and natural lakes in the mountain i-egion. If there 

 was the slightest tint of dissolved coloring matter in the streams, the wa- 

 ters when collected in these deep reservoirs could not fail to exhibit the color 

 much more deeply. Yet no one such fact is known, or is believed to have 

 existence. 



