COLLOIDAL SOLUTIONS

209

cholesterolbenzoate melts at 145.5° to an opalescent liquid which
at 178° became suddenly clear and isotropic. The optical
properties of this and other substances of similar behavior was
carefully studied by Lehmann. Schenck (1898), Eichwald (1905),
Buhner (1906), Bose (1907) and Dickenscheid (1908) have studied

9E

91

90

88

81

86

I

^7*1

0.&8

a
CQ

O.S1

0.86

115 120 125 130 135 140 145 150 155
Temperature
FIG. 75.—Fluidity-temperature curve (continuous) and specific volume-
temperature curve (dashed) of p-azoxyanisole. (After Eichwald (1905) and
Buhner (1906).)
the viscosities of these substances and shown that these so-called
"crystalline liquids" have a higher fluidity than isotropic liquids.
The specific volume of crystalline liquids is smaller than that of
isotropic liquids of corresponding temperature. In other words,
when an anisotropic liquid is heated to the clarifying point, there
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