36 
C. G. THORP, M.B., C.M. : 
Professor Ross is a fair average, estimating our effective atmo- 
sphere as 150 miles in depth and supposing the friction slowed 
the rate to nothing on reaching the earth, it would travel at an 
average pace of 20 miles per second in the one case, and 12 J in 
the other, and so would take exactly cither y\ seconds or 12 
seconds in its flight.* 
This seems to me scarcely enough to fuse this Australite 
(Plate XVIII, Fig. 6), weighing a little over a quarter of a pound, 
not to mention shaping it to a regular rotation form and cooling 
it again, yet at the same time it surely would be more than 
enough to disintegrate this small one of 4.9 grains (Plate XVIII, 
Fig. 5), with a fusion point so much lower than that of siderites. 
1 have just heard from Mr. J. B. Scrivener, the Geologist to 
the Federated Malay States, that in the Singapore Museum are 
two obsidianites weighing respectively 11} and 14 J oz. avoirdupois. 
He does not describe their shape, and is unable to find any record 
of their origin. 
The surface of the large one, however, if it had taken such 
a flight, must have chipped and chipped till it would have been 
very unlike the very fairly smooth object we see here. I think 
we can certainly infer from this that it is not a meteorite. 
This large Australite was found by Sir John Forrest in the 
interior of Western Australia when he was on one of his overland 
trips, and I have to thank Mr. Woodward, of the Museum, very 
much for his kindness in allowing me to exhibit this valuable 
specimen. 
I think it may very pertinently be asked why none of these 
glowing falling stars reach us as metallic Australites, or even 
Moldavites. I refer, of course, to their shapes. Sir G. H. Darwin 
says, in his book on tides, that they can only be produced in the 
absence of external gravity. Anyway, the forms in which 
Australites are found are not rotation forms in which the upper 
and lower hemispheres must necessarily be symmetrical and 
equal, and thus the equator equidistant from the poles and 
rounded, not sharp. Even the lens form is not symmetrical above 
and below ; it has a sharp edge round it which is not a true 
equator. The ordinary conical form is no more symmetrical 
than the button shape found in the Eastern States, from which 
Mr. Dunn supposes it to be derived. 
I regret I cannot altogether agree with Mr. Dunn in this, as 
the fracture facets round the cone reach much further towards 
the smaller disc than would be possible if they were derived from 
* Since writing this paper I learn that siderites of quite small size are 
found , in fact they are not uncommon, but they are shapeless angular frag- 
ments and their number by no means corresponds with that of falling stars, 
as stated above. Very small aerolites are also found, and the same remarks 
apply. 
