PROCEEDINGS OP SECTION C. 195 



of a series of small bodies which showed a series of forms 

 entirely comparable with those exhibited by Australites. 

 These minute bodies had been formed in the smoke 

 boxes of locomotives, and examples may be collected 

 along railway cuttings and about the locomotives them- 

 selves. There is no doubt that these little slag bombs 

 were formed by rotation while liquid, and the natural 

 inference is that the Australites though much larger 

 could have been produced in a like manner. 



Origin. 



Although numerous explanations of the origin of Australites and 

 related bodies have been advanced at various times, most of them 

 cannot be seriously considered. 



Professor E. P. Merrill* has recently advanced the hypothesis that 

 these bodies are nothing more than rolled pebbles of Obsidian, and he 

 quotes occurrences of pebbles of Obsidian which he considers were 

 derived in this manner. It is self evident that Professor Merrill is not 

 familiar with the forms that Australites assume, as otherwise he would 

 recognise that his hypothesis was contrary to known facts, and quite 

 untenable. 



Professor J. W. Gregory* has lately re-advanced the hypothesis 

 that Australites were produced by. the fusion of dust by lightning 

 discharge. Mr. Dunn* also suggests this as a possible origin of some 

 of the tektites. In this case no arguments whatever are advanced in 

 support of the assumption, and there are certainly no obvious arguments 

 in favour of it. 



One naturally wonders what density of dust would be necessary 

 for it to be possible for a flash of lightning to cause the fusion and aggre- 

 gation of a sufficient number of dust particles to form a body of the size 

 of an average Australite, and, further, under what conditions dust of 

 the requisite density could be so widespread as to account for the 

 distribution of Australites. If we assume that the Australites were 

 formed during more than one dust storm, we only partially get over 

 the trouble of distribution, and are then faced with the difficulty of 

 explaining the similarity of composition which the Australites have 

 been shown to possess. 



Dust storms accompanied by lightning discharge are by no means 

 uncommon in many parts of the world, but, so far, there is no record 

 of any such phenomenon as a shower of Australite-like bodies, even of 

 diminutive size. 



Years ago many believed that the tektites were of volcanic origin, 

 but this view has now been abandoned by most observers. In the case 



* 0). cii. 

 G 2 



