176 On covered Earth as a Manure. 



the cost, and comparini^ the expense with the effect pro- 

 duced as a inaniire, the farnnier would be enabled to de- 

 cide whether it would be profitable to adopt such a plan 

 to enrich his land or not. /i / - 



[Plaster siiews, with me, no signs of failure. Nor will it 

 with any other, when properly treated. 



It is well known to those who have collpcted the materials 

 for producing salt petre, that old mud walls, earth thrown up 

 in covered ridges; that found in cellars, under old buildings, 

 and other places not subject to rains and floods ; are impreg- 

 nated with nitre abundantly. This salt is found in caves in 

 our western country, to a great extent. No doubt the earth 

 mentioned in the foregoing communication was thus rendered 

 fertile. But the mixture of soil produces wonderful effects, 

 even where no such impregnation occurs. Instances could be 

 given in numerous cases. A member of this Society, (John 

 Curwen, Ksq ) many years ago levelled an almost barren hill, 

 adjacent to a piece of bottom land, which had heretofore pro- 

 duced only coarse and worthless herbage; but by hauling and 

 5?preading over the soil from the hill, the bottom land was con- 

 verted into a most profitable meadow ; which threw up luxu- 

 riant crops of the best grass — the green grass fpoa viridis,) &c. ; 

 without any other manure or auxiliary. To me this was not 

 surprising, for I have experienced the like effects often. 



During the revolutionary war, and especially atitscoramence- 

 ment, necessity compelled our searching for nitre in every way 

 and place. 1 was often surprised by finding it where it was 

 least expected. In dry sheltered earth, thrown up in ridges 

 covered by sheds ; in the sites of dilapidated buildings ; dry 

 cellars, slables and barns, and frequently in caves, and such 

 depositories. Common earth, thrown up in ridges and sheltered 

 from rain, lying for months exposed tp the influences of the 

 air, would be impregnated... ^e had; np;t then access to the 

 stores of this article now common in western caves. Nor did 

 we then dream of possessing a country which affords ample 

 stores of materials for war, as well as for the arts of peace. A 

 spot covered by an old pile of lumber,— even by a single board 

 —that under a brjasli heap long neglected — will become strik- 

 ingly fertile. See our 1st vol. p. 329, 330. 



R. Peters.} 



