No. 144.] 503 



any one crop can use in a season, to ensure a good growth, and 

 that no one plant during its life time, can succeed in eflfectingany 

 great change in the saline constituents of the ground around it. 

 When the soil has been deteri rated in this country in any marked 

 way, it has taken a succession of crops to effect it, and then this 

 result has been gradually induced. There has also been generally, 

 a downward rotation— a rotation from those richer in ash to those 

 poorer. Thus we see that the soluble saline constituents of the 

 soil, seem to be governed by the same general laws that govern 

 «aline impregnation under common circumstances, or as soon as 

 these matters were exhausted from the soil, an abrupt period would 

 be put to the growth of the plant. The existence ot a scanty growth 

 of pine, and other woods deficient in ash, on such exhausted soils, 

 is an illustration. 



One hundred pounds of the ashes of the beech contain enough 

 of inorganic elements for 15,000 lbs. of wheat. Now, though 

 most Soils are benefited by the application of ashes, yet in no 

 particular instance have any such more than a hundred fold re- 

 sults been verified; nor, indeed, are they claimed,! believe, even 

 for any of the soluble salts. Though ashes, leached and un- 

 leached, had been applied to the fields to which I have alluded 

 in a bountiful way the previous year, while they were planted 

 with potatoes, yet there was a great variation in the amount of 

 the corn crop on the two, and that variation was most consonant 

 with the amount of the manure applied. When this land was 

 put to corn without stable manure there was no crop of any ac- 

 count. 



From the soil of Virginia has been removed, by the successive 

 crops of tobacco, 1200 lbs. of the alkalies per acre — (I quote 

 from the Treatise of the London Society for the Promotion of 

 Popular Instruction) — and with this gradual drain has been a 

 gradual exhaustion. As far as the saline constituents are con- 

 cerned in the fertility of soil, the diiference, then, between a ier- 

 tile and a barren soil must be comprised within this limit of 

 1200 lbs. to the acre. If we sujtpose that a cubic foot ot water 

 weighed GU lbs., and if we assume that a cubic foot of soil weighs 

 100 lbs., we may readily calculate the weight of an acre of land 



