336 



cutting it, the produce was judged to be double that grown on 

 any equal number of feet in the same field. The beneficial ac- 

 tion of this substance, however, seems not to have extended 

 beyond the first crop ; as, since that was removed, no appear- 

 ance of superior fertility has marked the spot where it was 

 spread." 



O. M. Whipple, of Lowell, the proprietor of a large estab- 

 lishment for the manufacture of gunpowder, in which much 

 of this material is used, has favored me with successive com- 

 munications on this subject, which I can do no better than 

 present in his own language. 



" It is now about sixteen years since I commenced using salt- 

 petre. The grounds upon which I have used it, have yielded 

 large crops, and have held out much longer than grounds in 

 general, of the same quality of soil, and of the same kind and 

 quality of dressing commonly used. 



The kind of saltpetre which I have used, has been that part 

 extracted from the common saltpetre while undergoing the 

 process of purification, and is not fit for gunpowder. I have, 

 therefore, not been particular as to quantity, using what I have 

 had to spare ; but 1 am satisfied that it requires but a very 

 small quantity to produce favorable results ; I have thought 

 that one hundred and fifty pounds per acre, would be a suffi- 

 cient quantity to be used generally. The best mode of using 

 it, is to mix it with barn manure, meadow mud or any kind of 

 compost which may be at hand ; although I have used it in 

 various other ways, as I shall now describe. 



I have one piece of ground of 2f acres. It had been used 

 for a long time as mowing ground, and had, as it is termed, 

 run out, and grew but a very small crop of grass, say 1500 lbs. 

 to the acre. I ploughed it in the fall of 1830; in the spring 

 of 1831, I covered it with barn manure, mixed with saltpetre, 

 as described above, and harrowed it in, and planted corn with- 

 out disturbing the furrows. I had a very handsome crop of 

 corn. In the spring of 1832 I again dressed it as before, that is, 

 with barn manure and saltpetre, sowed oats and stocked it down 



