188 Henry C. RiehanJs : 



The percentages of alumina, ferric oxide, magnesia and lime in 

 the dissolved oxides were then calculated from the analyses of 

 the dissolved material, and are as follows : 



Table of Analyses of Material lost by Chemical Action 



OF Acids. 



Alumina 



(Al,03) 

 Ferric Oxide 



(Fe,03) 

 Lime 



(CaO) 

 Magnesia 



(Mg-0) 



An examination of these tables shows that all the stones are 

 more or less attacked by mineral acids, but that m the case of 

 the fine-grained Egerton and Greendale stones there is a slight 

 increase in weight, due probably to the formation of some new 

 salt in the stone. Tlie effect on the Stawell, Dunkeld, Egerton 

 (both fine and coarse) and Greendale stones is very small, the 

 Bacchus Marsh and Sydney stones are acted on considerably, 

 and the Apollo Bay, Barrabool Hills, and Darley stones are 

 affected to the greatest extent. 



The mechanical loss is small in all the stones, with the ex- 

 ception of the Darley, but unfortunately a mishap took place 

 with the insoluble portion of this stone, and time did not allow 

 of a repetition of the experiment. 



A perusal of the analysis of the dissolved material shows that 

 in the Barrabool Hills and Apollo Bay stones a large percentage 

 is alumina and ferric oxide, the ferrous iron dissolved from 

 these stones being determined in the ferric state. The Barra- 

 bool Hills material contains more alumina and ferric oxide, and 

 less lime and magnesia than the Apollo Bay stone. 



In the case of the Sydney stone, more than 80 per cent, of 

 the dissolved material is ferric iron, obtained from the solution 



