OF GLASS, AjN'D THE EESISTANCB OF GLASS VESSELS TO COLLAPSE. 
Summary of Results. 
Table V.-— Resistance of Glass Globes to internal pressure. 
281 
Number of 
experiment. 
Description of glass. 
Diameter, 
ill inches. 
Thickness, in 
parts of an inch. 
Bursting pres- 
sure, in pounds 
per square inch. 
I. 
11 . 
III. 
IV. 
V. 
VI. 
>> Flint-glass 
••X 
4-0 
4-0 
4- 5 
5- 1 
X3-98 
X3-98 
4 
X4-55 
X5-12 
G 
0-024 
0-025 
0-038 
0-056 
0-058 
0-059 
84 
93 
150 
280 
184 
152 
XII. 
XIII. 
XIV. 
XV. 
Green glass 
L 
4-95 X 5-0 
4*95 X 5-0 
4-0 X4-05 
4-0 X4-03 
0-022 
0-020 
0-018 
0-016 
1 r 
Crown-glass... <| I 
L 
4-2 X4-35 
4- 05 X 4-2 
5- 9 x5-8 
6 0 X 6-3 
0-025 
0-021 
0-016 
0-020 
90 
85 
84 
82 
120 
126 
69 
86 
Table VI. — Resistance of Glass Cylinders and Ellipsoids to internal pressure. 
Number of 
experiment. 
Description of glass. 
Form of vessel. 
Diameter, 
in inches. 
Thickness, in 
parts of an inch. 
Bursting pres- 
sure, in pounds 
per square inch. 
VII. 
Flint-glas.s 
Cylinder 
4-05x7-0 
0-079 
282 
XVI. 
Crown-glass 
Ellipsoid 
4-1 x7-0 
0-016 
80 
XVII. 
Crown-glass 
Ellipsoid 
4-1 x7-0 
0-019 
109 
Section IV.— ON THE RESISTANCE OF GLASS GLOBES AND CYLINDERS TO AN 
EXTERNAL PRESSURE. 
Ihe following experiments are in continuation of, and supplementary to the researches 
on the collapse of wrought-iron vessels already alluded to. In this aspect they are the 
most important in their bearings and the most novel of any in the present memoir. 
T-he method of conducting them did not differ in any essential detail from that 
pursued in the researches upon wrought-iron tubes, described in a former paper. A 
number of globes of varying dimensions were procured, and hermetically sealed by 
means of the blowpipe. In this state they were fixed in the interior of the strong 
wrought-iron boiler B (fig. 10) (capable of sustaining a pressure of about 2600 lbs. per 
square inch), in the position shown at A. The boiler or vessel B communicated by 
means of the pipe a, with a hydraulic force-pump having a plunger of three-quarters of 
an inch diameter, so that a uniform pressure of about 1000 lbs. per square inch could 
easily be obtained. In order to register the pressure, gauges of the Schaeffer construc- 
tion (C) were employed, as before, affording, within small limits of error, certain and 
accurate indications of the increase of pressure obtained by the pump. The collapse of 
2 I 2 
