192 



R. T. BAKER AND J. NANGLE. 



Effect of Heat on New South Wales Building Stones — continued. 



No. 



Eock Treated. 



Temp, of 



Furnace 



°C. 



Time in 

 Furnace 

 Minutes- 



How Treated and Remarks. 



Bundanoon 

 Sandstone 



)> n 



?5 5) 



)> 53 



Bundanoon 

 Sandstone 



10 



11 



12 



13 



>> •>•> 



Willoughby 

 Sandstone 



55 )5 



Bowral 

 Trachyte 



751 



25 



785 



20 



792 



15 



822 



20 



674 



30 



674 



30 



674 



30 



674 



30 



843 



15 



Change in colour very slight, 

 faint crack appeared across 

 the cube at right angles to 

 surface of water. No change 

 in texture. 

 Plunged suddenly into cold 

 water at 11° C. Deepening 

 of colour hardly perceptible, 

 small piece flaked off from 



edge. No 



change 



in 



into cold 

 unaffected, 



one 

 character. 



Plunged suddenly 

 water, entirely 

 edges unchipped. 



Half submerged in cold water. 

 A prominent crack and one 

 very small crack at once 

 appeared at right angles to 

 the surface of the water. No 

 change in character. 



The specimen was placed in the 

 furnace which was gradually 

 heated for half an hour, when 

 the temperature was ascer- 

 tained and the specimen taken 

 out and a spray of cold water 

 played on it till cooled. The 

 result was nil. 



Similar treatment to No. 9, 

 with almost similar results, 

 only a slight breakage on one 

 edge. 



A coarser grained stone than 

 No. 9, changed slightly in 

 colour, otherwise similar re- 

 sults to No. 9. 



Ditto ditto 



Suddenly plunged into cold 

 water; badly cracked in several 

 places, colour changed to dark 

 brown. 



