146 LAWRENCE HARGRAVE. 
The strop for the kite line (D) and that for any kites that may 
be flown above (A), pull on to the tie of the forward cell, so that 
no special rigging is required for tandem flying. 
The fabric of the surfaces can be adjusted easily to any degree 
of tension by the ties (B): previously it required some effort to 
fleet the boom shoes along the main frame. 
The booms (C) for pushing out the jackyards (E) are of plano- 
convex section instead of being round ; this adds a little to their 
weight, but something is gained by the reduced head resistance, 
and the lift due to the plane underside of the booms. 
The booms for the lower corners are continuous, those for the 
upper corners are joined at the crossings by tape or string hinges 
to the continuous booms, this brings all compressions of the truss 
work of each cell into one plane. : 
The outer ends of all the booms have wooden cleats (R) lashed 
on top and bottom, so that the jackyards (E) fitting exactly 
between them, receive the thrust truly square. The inner ends 
of all the booms are quite square and rest in beds on the main frame. 
There are no metal ferrules, joints, nails, or shoes on the kite. 
The sticks for bending the surfaces (F) have a versed sine of 
1-125 inches, They are not steamed, or held bent by a cord or 
wire. They are simply made in two or three layers of wood 
united with glue. The sticks retain the form given them and 
acquire an extra stiffness due to the glue. 
The total weight of this ninety square feet kite is twelve and 
a half pounds ; at least a pound of this might be saved by using 
light muslin instead of calico. 
The lifting power at the ultimate strength of the structure is 
not known ; it is estimated to be about three pounds per square 
foot, and that a wind of thirty miles per hour would not break it, 
or make it dive. This kite was flown on July 22nd, at 2 p.m. 
You will remember the weather as reported in the Sydney Morn- 
ing Herald next day. One of the jackyards broke at a small nail 
hole, and one pair of booms fel] to the ground, but the kite con- 
