696 
MR. FAIRBAIRN’S EXPERIMENTAL INQUIRY 
Assuming tlierefore the strength of the plates to be 1000, we have — 
For the strength of plates of equal sections 1000 
For the double-riveted joints 933 
For the single-riveted joints 731 
We may safely assume these ratios as the comparative values of jointed plates of 
equal sections when acted upon by a force calculated to tear them asunder. 
The correct value of the plates, computed from a sectional area taken through the 
rivet-holes, will therefore be to their riveted joints as 100, 93 and 73, or in round 
numbers as 10, 9 and 7- 
In addition to a loss of nearly one-tenth in the double-riveted joints, and three- 
tenths in the single ones, it will be observed that the strength of the plates is still 
further reduced by the quantity of iron punched out for the rivets. 
Table XI. Single riveted Plates. 
No. 
of 
exp. 
Description of plates 
and mode of riveting. 
Weight 
laid on 
in lbs. 
Changes produced by 
weight. 
Breaking 
weight 
in lbs. 
40. 
Plates same as be- 
fore, '22 inch thick, 
with overlap joint and 
double rivets ; coun- 
tersunk on one side ; 
AB = 3i inches; five 
rivets, each f dia- 
meter 
19,675 
Plates bent in a right 
line ; doubtful whether 
the joint would hold 
water 
23,707 
41. 
Plates the same 
strength, but different 
from the last in having 
only f-inch rivets all 
in a line ; AB = 3i ins. 
14,839 
Plates bent into a right 
line with the fixing 
16,351 
42. 
Same as last, ex- 
cept in not haring the 
rivet-holes counter- 
sunk; lap 1^ inch; 
AB = inches 
14,839 
Joint sound 
16,351 
Form of specimen and 
mode of fracture. 
Remarks. 
Fig. 11. 
By the word countersunk is under- 
stood a conical recess on one side of 
the plate to receive the head of the 
rivet, in order that it might not pro- 
ject beyond the surface of the plate. 
Tore across the three rivet-holes. 
In an unsuccessful experiment 
made before this upon plates preeisely 
the same, and riveted in the same 
manner, they were torn across the 
rivet-holes in attempting to lay on 
18,667 lbs. 
Plates tore across the rivet-holes. 
All the rivets on one side were cut 
in two in the middle, and the plates 
left sound. 
The results in the two last experiments, in the above Table, are identical as to 
strength. In the first, with the countersunk rivets, the plates were torn asunder, and 
in the latter the rivets appear tlie weakest, owing to the increased sectional area of the 
plates, which in the preceding experiment was reduced by countersinking the rivets. 
In both experiments it will be observed that the strengths of the rivets are propor- 
tional to the strengths of the plates, their powers of resistance being equal, or neaily 
so. In forty-one experiments the sectional area of the rivets was to that of the plates 
as *340 to *347, that is, the sections were nearly equal ; and in forty-two experiments 
as *34 to ‘44, which accounts for the nature of the fraeture in both cases. 
