40 8 Major-General Roy’s Account of the 
three feet from each other ; and being braced diagonally, are 
mortoifed at top into circles of the lame fort of wood. Over 
this circle, a fquare table of about n| inches is fixed, com- 
pofed of oak, and mahogany at top ; but both taken together 
do not exceed r| inch in thicknefs. 
The nature of the moveable ftands, whereof there were at 
laft no fewer than feventeen provided, will be comprehended 
from the reprefen rations of them towards the right-hand in 
tab. XVIII. and XIX. Their general conftruflion, in what 
regards the part of them which is fixed, differs not from that 
of the others, excepting that they were of different heights,., 
from two feet to about two feet eight inches, fo as better to 
fuit the irregularities of the ground where it might be necef- 
fary to place them. In the middle of each of thefe, an hexa- 
gonal wooden pipe defcends, from the top to within two or 
three inches of the bottom, where it is joined by a brace 
reaching from each leg. This pipe receives the common, 
cheefe prefs wooden fcrew (having three fid.es i crewed and. 
three plane), to the top of which the fquare table is attached. 
It is embraced by the circular nut, or winch with four handles,, 
whereby the table is elevated or depreffed at pleafure ; and being, 
brought to its proper height, is there made perfectly faft by. 
means of the flat- headed iron fcrew, which palling through, 
one of the legs, prefles an iron plate, fixed in the infide of the 
pipe, againft one of the plane hides of the fcrew. 
In defcribing the deal rods-, there has already been occafion to. 
make mention of the vertical and horizontal clamps, whereby the 
crofs-feet are faftened to the table on the top of the hand. The na- 
ture of thefe tables will be heft underflood by confulting the two 
plans of them towards the right hand in tab. XVIII. ; whereof 
one reprefen ts the two grooves fitted for the alternate reception 
of 
2 
