fF o3e54 
6. Is the earth as thoroughly pulverized by plough- 
ing and harrowing, as when dug with the fpade? 
The previous ftate of the foil fhould be known; 
the expence of digging an old ftiff ley would be 
very great; perhaps, the fpade following the plough 
would be beft. 
4. What is the difference of expence per acre, in the 
two modes of cultivation? 
I have no actual experience in fuch a comparifon; 
but have no doubt, the fpade would fully compenfate 
the extra expence, 
VII. CONCERNING SUBSTANCES IN THE EARTH, 
INJURIOUS TO VEGETATION, 
1. Have you found any fubftances in the earth in- 
jurious to vegetation; and of what nature are they? 
Excepting a few vegetables, and until reduced to 
earth, I have found afhes of foffil coal hurtful, the 
root cankers, and becomes a nidus for worms. 
2. Have you difcovered any means of preventing 
the injury to vegetation done by thofe fubftances? 
3- Is there not an aftringency in peat mo/s, boftile to 
vegetation? How is that to be corretted? 
4. Why do you prefer putting American, and other 
foreign plants, into peat? And are there any other 
kinds of plant, as celery, Se. that thrive particularly 
well in that foil? 
5» Are not aluminous and metallic fubftances in the 
foil, hoftile to vegetation? 
6. Have 
