METEOKIC DUSTS, N.S.W. 



255 



flakes. The magnetic material was found to contain both 

 cobalt and nickel. 



The comparatively large quantity of magnetic matter in 

 the three Sydney dusts is probably due to the lighter 

 materials having been gradually removed ; i.e., the two 

 dusts had been subjected to a process of vanning by air 

 currents and the mud had been concentrated by the water 

 flowing in and out of the cistern. 



These dusts collected in Sydney confirm the results 

 obtained by M. Tissandier and others; it was thought 

 sufficient to ascertain the presence of cobalt and nickel. 

 The quantitative analyses were not undertaken as they 

 would have occupied a great deal of time and would have 

 afforded but very little more information. 



Meteoric Dust from Uralla, collected by Mr. Oleghorne, 

 December 14th, 1883. A fine reddish dust with some 

 angular grains ; most are clear and colourless, but some 

 are yellow or red. Like the other red dusts it contains 

 granules of concretionary calcium carbonate, which dissolve 

 with effervescence in acetic acid, also particles of charcoal 

 or decayed vegetable matter. The average size of the 

 grains is from *01 to *02 mm. 





Analysis. 





Moisture at 100° 



... ... 



... 4*25 



Silica 



... 



... 70*60 



Iron sesquioxide 



... 



4*66 



Alumina 



... ... 



18*74 



Lime 



... ... . 



•70 



Undetermined... 







1*05 



100*00 



Mr. Oleghorne in writing from Uralla on December 14th 

 1883, says, " I enclose herewith a sample of dust which 

 fell in this neighbourhood yesterday (Thursday) morning. 



