According to Reichenbach, paraffine may crystallize in three forms:
needles, angular grains, and leaflets having the luster of
mother-of-pearl. Hofstadter, in an article on the identity of
paraffine from different sources, confirmed this statement, and added
further that at first needles, then the angular forms, and then the
leaflets are formed. Fritsche found, by means of the microscope, in
the ethereal solution of ozokerite, very fine and thin crystal
leaflets concentrically grouped, and in the alcoholic solution fine
irregular leaflets. Zaloziecki has recently developed these
microscopic investigations to a much greater extent. According to this
observer, the principal part of paraffine, as seen under the
microscope, consists of shining stratified leaflets with a darker
edge. The most characteristic and well developed crystals are formed
by dissolving paraffine in a mixture of ethyl and amyl alcohols and
chilling. The crystals are rhombic or hexagonal tablets or leaves, and
are quite regularly formed. They are unequally developed in different
varieties of paraffine. The best developed are those obtained from
ceresine. Their relative size and appearance give an indication as to
the purity of the paraffine, and, as they are always present, they are
to be counted among the characteristic tests for paraffine.
Reichenbach observed that mere traces of empyreumatic oil prevented
their formation.
Pages:
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119