GYPSEOUS EARTH. 459 



benefit whatever. The inferences which I drew from all my expe- 

 rience (and there existed scarcely any other known facts or experi- 

 ments), were that this earth as manure acted in the same manner 

 as gypsum, though more powerfully and in no other manner than 

 as gypsum would under like circumstances ; that like gypsum, on 

 my land certainly, and as I inferred in our tide-water region gene- 

 rally, this earth had no effect whatever on any acid soils and rarely 

 on any other crop than clover (and other leguminous plants), even 

 when properly applied on neutral or calcareous soils ; and that when 

 naturally acid soils were made calcareous by being marled, this 

 green earth then became generally operative thereon as a manure 

 for clover (and for other plants of the clover or pea tribe), in the 

 same manner as is usual in regard to gypsum.* And though the 

 effects, when any were produced, were greater than those of any 

 usual or known dressings of gypsum, and sometimes in a very re- 

 markable degree, still the failures and disappointments were so many 

 that I did not deem the practice worth being continued. In 1841, 

 my son, the present occupant of the Coggins Point farm, at my 

 request, recommenced the applications of gypseous earth, for ex- 

 periment; and on the clover of this year, 1842, he has extended 

 the dressings over more than 60 acres. f The results were, as in 

 former years, very unequal, and for the greater space of ground 

 covered, unprofitable, and barely if at all perceptible. But on 25' 

 to 30 acres the benefit was remarkably great, and in some cases (of 

 summer dressings) improvement was obvious within ten days after 

 the application. But what was most interesting in the results was, 

 that a clue seemed to be thereby furnished to explain the frequent 

 previous failures of this manure, even when applied to clover grow- 

 ing on neutral or calcareous soil, which are the only circumstances 

 in which it has ever been found profitable in practice. My former 

 applications had been generally made from the upper and greener 

 stratum of the gypseous earth (designated in a succeeding page as 

 (7), or if from the lower and blacker part (77), the digging did not 

 penetrate more than a foot, or, at most and rarely, two feet below 

 the before exposed outer surface. But in the recent larger opera- 

 tion, the digging (made on the river beach) was so much more ex- 

 tensive, as to furnish earth from depths of three or four feet, as well 

 as of portions nearer to and at the surface. I ascribed the remarka- 

 ble differences of effect to the kind and place of the earth ; inferring 

 that the exposed parts, and all perhaps near the surface, had, by 

 exposure to air or water, lost a large proportion of the soluble or 



* See these views more fully set forth in the article above referred to, 

 and also in another on the green-sand marls of Pamunkey, at pp. 679 and 

 G90, vol. viii. Farmers' Register. 



f See the facts and results stated in two communications to Farmers' 

 Register, pp. 86, 135 and 252, vol. s. 



