( 3S ) 
as many inches or parts of an inch as T mean to 
give to the road a rise or fall, which, perhaps, on 
experiment in a small distance, I may find requisite 
to alter to more or less, as I perceive the road 
likely to come out at the point at which I wish it to 
terminate. An elevation of an inch in a foot makes 
a very easy rideable road :—above it, is too steep ; 
and less, lengthens the distance unnecessarily, ex¬ 
cept the point desired to arrive at can be attained 
with less slope, or you want to make a cart-road. 
Thus, if your level is six feet in length, the difference 
of the length of the legs should be six inches ; and 
its figure should be as represented in the plate. I 
have also subjoined the figure of a more elaborate 
one. 
The mode of using it is as simple as its construc¬ 
tion. Two persons to carry and place it will be 
required, and a third to carry picquets. If to de¬ 
scend, the long end is carried foremost ; to ascend 
the short one. In either case, the hinder person 
places one foot of the level on the place the road 
is to commence from, under which he drives in a 
picquet horizontally ; the foremost operator then 
places the foremost leg on the ground, moving it 
either to the higher or lower part of the surface (the 
hinder one keeping his end fast) till the line to 
which the plummet is suspended hangs over the 
perpendicular line marked upon the upright board ; 
he then receives from the carrier a picquet, which 
he drives in horizontally under that end of the in¬ 
strument. lie then proceeds forward, and the 
hindmost 
