METEORIC DUSTS, N.S.W. 283 



not appear to quite account for the phenomena, and it 

 appears to be desirable that sufficient evidence is needed 

 for each to judge for himself. My own opinion is that the 

 phenomena of dry fogs or haze, of dust storms and mud rains 

 are not due to extraterrestrial causes ; I think that the 

 material or dust is mainly made up of debris, inorganic and 

 organic, from the land and occasionally as everyone is aware 

 of volcanic dust; mingled with this undoubted telluric 

 matter there appears to be nearly always a certain amount 

 of extraterrestrial or cosmic matter, i.e., the dust or debris 

 of meteorites, although in most cases it is very difficult or 

 even impossible to discriminate between the terrestrial 

 and the cosmic dusts. 



The presence of cobalt and nickel iu the iron of a dust 

 was formerly regarded as a proof of its meteoric origin, 

 but it is now known that both of these metals occur in the 

 metallic iron met with in some rocks, and notably in the 

 telluric irons of Greenland, nickel has also been found in 

 dust from volcanoes, and in the soot from coal smoke by W. 

 Noel Hartley, f.r.s., and Hugh Ramage, (Proc. Roy. Soc, 

 March 1901, p. 97). They also found other metals in soot, 

 e.g., copper, gallium, thallium, silver chromium, lead, etc. 

 Both nickel and cobalt occur in some varieties of com- 

 mercial iron and steel, cobalt is especially likely to be 

 present in traces in Bessemer or other steel in which 

 spiegeleisen or other manganese alloy is used in the manu- 

 facture. A piece of a Sydney tram rail, a horse shoe picked 

 up in the street and nails from the same all yielded traces 

 of cobalt; nickel was not tested for as the presence or 

 absence of cobalt was regarded, for the purposes of this 

 inquiry as of more importance. 



In spite of the presence of cobalt and nickel in some 

 telluric irons, dusts and soils, I still think that some, if 

 not most of the metallic iron (containing nickel and 



