CALCAREOUS MANURES— APPENDIX. } 79 



evident to the eye in the black waters of so many ponds and streams, all 

 this lost fertilizing matter must be in very small proportion, compared to 

 the greater quantity that is carried more gradually and frequently into 

 the earth. Much the greater part of the wood-land of lower Virginia is 

 most freely and abundantly thus supplied, not only because of the abun- 

 dant sources presented in a thick layer of fallen leaves, the growth of 

 many successive years, but also because of the very level surface of the 

 land, which obstructs the flowing off of the surplus rain water, and the ge- 

 neral sandy and open texture of the soil and sub-soil, which operate to 

 absorb quickly the water and its dissolved vegetable matter. Yet it is 

 more especially these lands that show the least remaining and abiding store 

 of this supply of vegetable manure. The soil, or all of the upper part 

 which shows any color from containing vegetable matter, is usually not 

 more than two inches thick on sandy soils, and still less on the stiffest ; and 

 all the portion below, (though necessarily manured by being often soaked 

 to a foot or more with rain-water conveying all its dissolved vegetable ex- 

 tract,) is entirely barren and worthless. Such results would be as inex- 

 plicable as they are wonderful, but for the reasons afforded by the doctrine 

 of the combining and fixing powers of carbonate of lime and vegetable 

 salts of lime ; the absence of which ingredients is the sole defect in these 

 cases, and which, when present in soils, show results of fertilization altoge- 

 ther the reverse of these. Where lime is present in sufficient quantity, no 

 coloring or manuring matter is lost to the soil in the flowing off of surplus 

 water, nor in the wasteful and profitless decomposition of the greater 

 quantity of coloring and alimentary matter soaked into the earth. 



My observation was not attracted to the cause of the existence of black 

 waters, and this application of the facts, until nearly the close of my resi- 

 dence in the country, and of my opportunities for personal and accurate 

 observation. And I am well aware, and ready to admit, that previous ob- 

 servations, made by mere chance and without object, are worth very little 

 comparatively. I therefore would be glad to have the attention of other ob- 

 servers drawn to this point, and any facts to be elicited that will either confirm 

 or disprove my positions. From inquiries made of persons who have had 

 ample opportunity to observe what waters were either permanently black 

 or without tinge of such vegetable stain, I have heard the following general 

 statements of facts, on which my comments will be offered as the facts are 

 presented. 



Streams and ponds of black waters are rarely seen above the falls of 

 the rivers; and are believed to be very rarely found even twenty to 

 thirty miles above. They are never seen in the still higher lime-stone 

 region. If this opinion be correct, then these waters are confined exclusively 

 (as they certainly are mainly) to the region of soil of the most acid quality. 

 At the distance above the falls where black waters are never found, the 

 high land was naturally in general of good quality, and the bottom or 

 alluvial lands, on small streams, invariably of good soil. Of course these 

 qualities indicate more of lime in the soil ; and, according to my views, also 

 the inability of water to become black, or at least to remain colored.* 



The waters of Blackwater river and its tributary streams and swamps 

 become darker in autumn, owing to the low level of the surface at that sea- 

 -son. This is according to sound reason; as evaporation of the solvent fluid 

 necessarily increases the strength of the solution. But this cause is held 



* The extract translated from M. Puvis' ' Essaisur la Marne,' and introduced at page 

 150 of this essay, affords testimony that the facts in regard to the existence and localities 

 of black waters in France accord strictly with the views presented in this article. He 

 says there that, " during the month of August, the water of the ponds on calcareous 

 soil does not become blackish, as often happens in silicious ponds." 



