... 2-45 



... 12-78 



... 41-53 



... 3509 



... 7-66 



226 B. G. CORNEY, T. W. E. DAVID, AND F. B. GUTHRIE, 



analysis shows, practically a kaolinite, was probably originally a 

 dacite tuff. 



Moisture at 120° C 



Combined water 



Silica 



Alumina 



Oxide of Iron, (Fe 2 3 ) 



99-51 



The earth in question is very soft, of a pinkish colour, with 



redder patches of ferric oxide distributed irregularly throughout. 



The oxide of iron can be dissolved out with hydrochloric acid. 



The colour is unaltered on ignition. Moistened with water, the 



earth has the greasy feel and peculiar odour of moistened clay or 



kaolin. For analysis the sample was reduced to fine powder with 



very gentle pressure and separated from the harder quartz particles 



by means of a very fine sieve. Lime and magnesia are absent; 



alkalies were not determined. The silica, alumina and combined 



water are present in approximately the proportions required by 



the formula Al 2 3 (Si0 2 ) 2 (H 2 0) 2 ; the percentage composition of 



which would be — Silica = 46-51 



Alumina = 39 "54 

 Water = 13-95 



100-00 



The amount of silica found in the edible earth, if combined in 

 these proportions with the alumina and water, would require 35-30 

 per cent, alumina and 12-46 combined water, quantities which are 

 very close to those obtained by analysis. 



Assuming the material to be Al 2 3 (Si0 2 ) 2 (H 2 0) 2 containing 7 "66 

 per cent, ferric oxide and 2-45 per cent, moisture its composition 

 would be : — 





Calculated. 



Found. 



Moisture at 120° C... 



... = 245 



2-45 



Combined water 



... = 12-54 



... 12-78 



Silica... 



... = 41-81 



... 41-53 



Alumina 



... = 35-54 



... 35-09 



Oxide of iron (Fe 2 3 ) 



... = 7-66 



7-66 



100-00 99-51 



