STRENGTH OF GLASS.
626
A comparison of the rough, ribbed, wired, and polished plate shows the wired plate below the strength of the other kinds of plate. W ith respect to the rough, ribbed, and polished plate, each in turn shows higher strength than the others.	,	, ,
Taking into consideration the variation in strength displayed by individual specimens the results of these comparisons will be accepted provisionally, the evidence not generally being of a conclusive nature. The relative strength of lights set in frames in which the four edges are supported, compared with the transverse tests, where the lights were supported along two edges, shows the strength oi the lights m frames ranging from once to nearly twice the strength of the tians-
verse specimens.	.	״	.	£	,
Under direct compression the crushing strength of glass was found to be very great, showing values from 45,040 to the enormous strength of 84,000 pounds per square inch.
LIGHTS SET IN FRAMES.
Ultimate strength, pounds.
V x 8״. !	12" x 12".	16" x 16". |	20" x 20".
	Inch.	Inch.	Inch.
.16	.10	.17	.16
248	93	115	104
.21	.20	.20	.19
272	205	211	263
.26	.27	.26	.30
356	513	334	402
.43	.42	.36	.42
1,197	791	467	734
.47	.50	.47	.47
1,372	1,376	1,238	985
.15	.15	.13	.13
171	143	132	103
.22	.22	.22	.22
309	262	184	245
.29	.27	.27	.28
693	267	387	364
.37	.38	.35	.36
878	885	580	542
.52	.54	.50	.51
1,740	2,010	1,290	1,190
.83	.82	.75	.80
3,630	3,640	2,680	. 2,120
.81	.82	.75	.86
3,110	2,330	2,260	2,310
.99	1.06	1.02	.93
3,720	3,750	3,980	2,840
.97	.99		1.00
3,110	3,720	5,490	2,110
.28	.28	.29	.28
347	234	234	227
.40	.41	.38	.40
980	774	598	552
.54	.54	.53	.56
1,590	1,520	1,210	1,530
.53	.54	.55	.52
1,694	1,134	984	898
.28	.31	.28	.31
388	352	228	308
.38	.40	.38	.38
898	692	436	428
Factory.	Description.	Nominal
		thick- ness.
		Inch.
Appert		Rough, Lehr annealed...	* {
		do		X5 1
		do		4 1
		do		1 {
		do		£ {
		8 {
		t
		do		ïV i
		do		£ 1
		do		’ {
(Not known) —	Rough, oven annealed ..	4 {
		do		« {
		do		i {
		do		1 {
		do		1 {
	Wired, Lehr annealed,	! f
	sandwich rolled.	4 l
		do		i {
		do		5 ־j
		
Mississippi		Wired, solid rolled		*j
		4 i
XNUXUi.--J.1XC liguito v
thickness of that light.