[ 28 | 
. From thé almoft univerfal adoption of the practice, 
it feems that experience has fully juftified it. Inthe 
cafe of exotics that do not arrive to full perfe&ion 
in.an alien climate, it does not feem wonderful 
-but in the:cafe of naturalized vegetables, I cannot 
explain it. _ 
19. What foil is be/t adapted for nurfery pee; 
and why? 
20. How many crops will rich garden-ground pro- 
duce in.a year, in the neighbourhood of London? 
21. What is the beft rotation of crops in fuch ground? 
(22. How many fouls will an acre of garden-ground, 
properly cropt, maintain? / 
Il. CONCERNING THE AIR, 
1. What effect has the air in promoting the growth 
. Of plants, and bringing them to perfection? 
By checking the too rapid growth, it renders the 
plant robuft and firm; by its motion, it agitates the 
plant, and thereby contributes to its health, analagous 
- to exercife in animals—carrying off noxious effluvia 
from the foil, and putrifying leaves, and alfo the 
perfpirable exudation of the plant. 
2. Do you confider pure air to be neceffary for that 
purpofe? 
If by pure air be meant good atmofpherical air, 
undoubtedly yes. 
3+ Will fruit-trees produce fruit in London? Or 
within what diftance from that metropolis, are the 
differeat kinds of fruit produced in perfection? 
