IMPACT UPON BEAMS. 
113 
the middle of the beam, which was sustained at its ends A, B, 
in a horizontal position, by firm supports. The cylinder C was 
perforated by one end of an uniform light slip of timber D, 6 feet 
4 inches long, which was attached by a joint at the other end to 
the vertical prop E. 
It will be observed that C fell through small arcs of a circle 
instead of vertical; but as the radius was large and the heights 
usually small, the error was not worth notice. 
lbs. oz. 
Weight of leaden cylinder . . 13 4 
5- of weight of lever D (its \ 
inertia) ........ J 
Weight of striking body, or\ 
sum of the above ... f 
0 9 
13 13 
8th Beam.—This bar was of cast steel, and was that called 
the 3rd beam in our horizontal experiments ; it was now laid 
upon two supports 6 feet 6 inches asunder as before, and bent 
by impact in the same direction. 
Heights fallen 
through, in 
inches. 
Observed de¬ 
flections of 
beam from im¬ 
pact, in inches. 
Whole deflec¬ 
tions of beam 
or observed 
deflections 
-f* ‘33 inch. 
Calculated 
pressure, in 
ounces, which 
would produce 
the whole de¬ 
flections. 
Calculated 
heights fallen 
through, in 
inches. 
Excess of real 
over calculated 
heights fallen. 
3 
2’00 
2-33 
916 
2-53 
1 
IT 
6 
2*57 
2-90 
1140 
5-22 
1 
■S' 
9 
2*99 
3*32 
1305 
7-76 
x 
12 
3*40 
3'73 
1466 
10-69 
l 
V 
15 
3*74 
4-07 
1599 
13-45 
1 
TIT 
18 
4*15 
4-48 
1760 
17-19 
1 
TT 
21 
4-40 
4*73 
1859 
19-71 
1 
T 7T 
24 
4-68 
5*01 
1969 
22-72 
1 
TT 
Referring to the previous experiments on this beam, it will be 
found that the beam when placed on two supports 6 feet 6 inches 
asunder, bent *33 inch, as given in the 3rd column above, by its 
own weight; and that 1006 ounces laid on the middle bent it 
2*56 inches. 
The calculated heights of impact in the 5th column were ob¬ 
tained from the formula 
h = - 
e 
2 p w 2 - 
(w + r) (p — q) {p — q — 2 w). 
e . 
In this formula — is constant in pressures upon 
V 
1835. 1 
1 3rd. 
the same 
