Basalt. 
281 
hydrochloric acid. This was moistened again with 
acid; as it had gelatinised in three hours. The whole 
was transferred to a glass slide, and, after standing two 
days, was photographed. The figure shows the NaCl 
cubes just a.s they appeared in the strong acid, x 30 
diameters. 
Analysis of Bondi Basalt. 
Fresh undecomposed 
Basalt. 
Decomposed Basalt 
filling fissures. 
Silica 
. . . 43-50 
42-0 
Alumina. . . 
... 14-60 
40-2 
Ferric oxide 
. . . 5-40 
trace 
Ferrous oxide . . . 
8-28 
Lime 
... 8-70 
nil 
Magnesia 
... 616 
nil 
Soda 
... 7-34 
4-4 
Potash ... 
2-95 
1-6 
Titanic oxide 
■10 
Phosphoric oxide 
Chromic oxide . . . 
trace 
trace 
trace 
Manganese oxide 
trace 
Chlorine... 
•37 
W ater ... 
... 2-50 
12-00 
99-90 
100-2 
Specific gravity, 2*94. 
As one would have expected from the preliminary 
examination of the rock, the notable feature of the 
analysis is the large percentage of soda. I have 
already stated my reasons for believing that the rock 
contains sodalite. An analysis of the decomposed 
basalt is also given, where it will be noted that iron, 
lime, and magnesia have been extracted completely 
by natural weathering. 
