402 
a 
Bismuthbromide: BiBr,. 
2 Maximum Pressure H 
SG FA) ip et «| „Surface . >| : Molecular 
5 Soe mm. mer | ROE be ee Ps 
a in . mer- ravi ye in| 
| 5 Ër cury of | in Dynes es 4 Erg per cm. 
LE 0° C. | 
| ee ——— 
250 alate 3029 66.5 4.598 1407.6 
281 2.172 2893 63.6 4.525 1360.6 
299 2.103 2804 61.6 4.471 1328.5 | 
320 2.032 2709 59.5 4.416 ‘ 1293.8 Re 
346 1.936 2581 | 4.348 1245.7 
370 1.836 2448 53.8 4.286 1191.3 
| 389 1.774 2366 52.0 4.237 1162.3 
| 417 1.668 2224 48.9 4.164 1105.8 
442 1.575 2100 46.2 4,099 1055.8 
| Molecular weight: 447,76. Radius of the Capillary tube: 0.04381 cm. 
| at 150 C. 
Depth: 0.1 mm. 
The salt was prepared from the purest bismuth and bromine, and purified 
by distillation; it melts at about 250° C. into a yellow liquid, becoming 
darker at higher temperatures. At 271°.5 C. the density was: 4.572; at 301° C.: 
4.466; at 330° C.: 4.390. At f° C. itis generally : d4. = 4.598 — 0.0026 (f = 250°). 
The temperature-coefficient of » increases slowly from 1,76 Erg between 
250° and 389°, to about 2,0 Erg per degree at higher temperatures. 
§ 8. If now we review the results obtained, on comparison we 
can derive from them the following conelusions (vid. fig. 1). 
| 
| 
Name of the Substance: | Temperature-coefficient of #: | 
Sulphurmonochloride 2.24 to 1.79 
| Phosphorustrichloride 1.61 
| Phosphorustribromide 0.81 to 2.63 
Arsenictrichloride 1.40 
Arsenictribromide 2.05 to 0.98 
Men tionwnehiende 1.66 
' Bismuthumtrichloride 2.14 to 1.75 
Bismuthumtribromide 1.16 to 2.0 
