On a form of Flying-machine. 
By L. Harerave, 
[Read before the Royal Society of N.S.W., 2 December, 1885.] 
of the owing is 378 square inches ; the length of body aa head is 
6 feet 1 ; the area of the body and head is 858 square inches ; 
the total weight is 1:47 lbs. ; this gives an area of 840 square 
inches per 
Now as to ‘the motive power. The strut forms the back-bone of 
the whole concern ; it is about 11 in. square, and is hollowed out to 
about the thickness of cardboard, and you could easily flatten it 
between your fingers and thumb ; it is made of clear pine, and at 
5,400 lbs. per square inch would stand 3,051 Ibs. end compression 
if it did not buckle ; it is tapered slightly towards the tail. 
The twenty-four elastic hea weigh 5 ozs., and each is stretched 
with a force of 12-6 lbs. to 308 inches ; and in the manner they 
are arranged puts a shrcat of 189 Ibs. on the strut. 
_ The purchase by which the elastic bands are stretched is a luff 
cord is white hem fishing-line, and breaks with 67 Ibs. ; the theo- 
retical strain on the fall is 37-8 lbs. but experiment with a Salter’s 
balance on the string proves there is only 30 lbs., the rest being 
lost in friction at the four sheaves ; this strain —- as the 
india-rubber bands contract at the following rate 
Ist flap ... bins OO - The: 5th flap... -++, 19:2 Ibs. 
e BU ven nc dOS.y, Cthivge 6) ve jenn LED ig 
rd = 24. ,, 7th 4 156 ,, 
te mae 2 Gy oe 8th ,, : ie - 
