164 FOREST TREES. 
raising them three or four inches above the surface 
of the ground, to allow a free circulation of air un- 
derneath. These boards serve to support the screen, 
which is made of laths with a piece of lath nailed 
across each end. ‘The laths are placed about one and 
a half inches apart, not more. ‘The seed is sown 
broadcast, and raked in. The raking-in is an opera- 
‘ion requiring some skill and judgment, and is not 
io be trusted to a clumsy, awkward hand. After 
sowing, if the ground be somewhat dry, a light roller 
is passed over it, or a piece of a board with a handle 
attached, is pressed upon the surface. Some recom- 
mend a covering of fine sand or vegetable mould, not 
to exceed a quarter of an inch in thickness. When 
the sowing is completed, the screen is put upon the 
frame. This, in case of dry weather, will aid in keep- 
ing the surface of the beds moist until the seeds come 
up, which is a matter of importance. 
Another sort of screen is at present principally 
used by Mr. Douglas, not for its superiority or greater 
cheapness, but on account of the difficulty of pro- 
curing laths in sufficient quantities at wholesale 
prices. Rows of posts seven feet high are set ten 
feet apart, and eight feet distant in the rows. Fence 
boards, six inches wide and sixteen feet long, are 
nailed upon these at the top. Slender poles are laid 
across, and on these are placed bushes and branches 
of trees with the leaves on them. This sort of screen 
is constructed the sammer previous to sowing. The 
beds are so laid out that each row of posts is in the 
middle of a bed. If the soil is tenacious, it is best 
