34 
C. G. THORP, M.B., C.M. : 
of a pea or say about the same size as this small Australite of 
mine, fuses from atmospheric friction caused by its rapid flight, 
it has been pointed out to me that it must be the outside that 
first heats up, glows and fuses, this fused coating being instantly 
— in fact perfectly automatically wiped off by the air through 
which it is rushing thus exposing another surface to heat glow 
and fuse this being removed in the same way ; a still further 
surface is exposed and so on till the whole is gone ; thus it 
would leave a meteor-like tail of dust in its track which in due 
time would fall to the earth as cosmic dust of which many tons 
are believed to be added to the world every year. 
This view is supported by the glazed surface on some of the 
siderites shown. 
According to the latest theory that has been brought forward 
to account for the original formation of the world it is held to 
be almost entirely from these meteoric bodies, large and small, 
stony and metallic, that the globe as we know it has been built 
up, and indeed is still being built rrp and yet these curious 
regular bodies of uniform shapes are absolutely restricted to these 
rare and unique glass bombs and to quite small and detached 
portions of the surface of the globe. 
With regard to the rotation form on which Professor Kerr 
Grant lays such stress he says 
" The forms which a mass of liquid in motion is capable of assuming 
have been the subject of discussion by many eminent mathematicians from 
the time of Newton to the present day. Neglecting the effect of air resistance 
on the surface, it has been shown that the following forms are possible : — 
t. The Sphere— possible onlv when there is no rotation. 
2. The Oblate Spheroid— stable at low speeds of rotation. 
3. The Prolate Spheroid- stable, if at all, only at high speeds of 
rotation. 
4. The Apioid, or pear-shaped figure of revolution. 
5. The Dumb-bell or hour-glass figure of revolution. 
It is remarkable that all these forms, if we neglect secondary features, are 
comprised among those assumed by obsidianites. The occurrence of cigar- 
shaped and dumb-bell shaped figures is of particular interest, since the 
stabilitv of these types is still of dispute among mathematicians.” (Plate 
XXIII') 
Of course if one neglects the effect of air reistanoee on the 
surface and ignores secondary features which are both very 
important and suppose a molten mass of glass revolving in and 
rushing through the air which is a physical impossibility one 
can produce almost anything one desires in one’s own imagination. 
Professor Kerr Grant does not explain why these rotation 
bodies are never formed from siderites. 
If 1 per cent, of its latent energy when converted into heat 
would suffice to fuse an Australite it would require less than i| 
per cent, of the energy latent in a siderite to fuse it. Thus the 
heat generated by the friction of its flight- at least in the upper 
