38 
C. G. THORP, M.B., C.M. : 
dissociated and revolving separately as two distinct spheres, 
and the same may be said of the apioid form, which is really a 
globe and a satellite. 
The instability of these forms surely depends on the tendency 
of the two ends to become dissociated entirely from each other 
and to fly apart on account of the preponderance of the centrifugal 
force unless the rapidity of revolution is exactly correctly balanced. 
This apparently never occurs in nature, as twin stars or globes 
and satellites are always separate and never attached to each 
other. They either unite into one globe or become stable by 
separating to a certain distance from each other, which is capable 
of calculation. 
The rotation explanation of Australite shape formation does 
not take into consideration the, to me, quite self-evident fact 
that if such a rotation body, however perfect ifs shape and 
motion, struck the earth on the softest imaginable spot whilst 
in the most slightly plastic condition, even if it struck it exactly 
truly plumb to the surface, it must afterwards much more re- 
semble the Moldavites exhibited than the rigid mathematical 
shapes in which we find Australites showing no faintest sign of 
impact. 
Professor Kerr Grant says that he thinks he has seen signs 
of impact on one or two obsidianites. If his .explanation were 
correct it would not be one or two questionably, but every one 
very unquestionably, that as one might say would be all sign 
of impact and have no other shape. 
I make the suggestion, with some diffidence, but perhaps 
these Moldavites were endeavouring to become true rotation 
forms when they struck. 
My complete hypothesis founded on the premises and argu- 
ments I have laid before you in this address, seems to be that 
somewhere in the East India Islands, stretching along the whole 
of the north of Australia, is a volcano, or are volcanoes (it is 
not necessary to suppose that the volcano that produced the 
Tertiary Australites is necessarily the same as has produced and 
is producing the modern ones, nor that all the modern ones 
are produced by one and the same volcano) with craters con- 
taining a thoroughly fused plastic glassy lava of the correct 
composition, wherein bubbles of highly superheated steam or 
other gas rise with considerable force, carrying with them a thin 
pellicle or bubble of the lava with a bleb attached. These being 
shot upwards by the explosive force of emergence, combined with 
the rush of the large vertical column of intensely heated vapour 
over the cauldron, reach a height of several miles, and thus are 
carried above the lower atmospheric stratum, with its varying 
eddies, governed by the irregularities of the surface of the globe, 
