204 BUILDING STONES OF ST JOHn's CATHEDRAL, BRISBANE 



Compression Tests. 



Edge of Cube. Lbs. per sq. inch. Tons per sq. foot 



3 inches 4800 308-5 



3 inches 4861 312-5* 



3 inches 5645 366-9* 



3 inches 5747 370-1* 



Absorption Test. 



This gave a value of 3-65 % by weight and 8*40 % by 

 bulk, which, in comparison with other sandstones, is fair. 



Attack by Carbon Dioxide. 



To ascertain this a current of carbon dioxide gas was 

 passed continually for 3 weeks through water containing 

 the stones in two-inch cubes, and as a result, 0*03% by 

 weight was lost ; this is an excellent result. 

 Attack by Mineral Acids. 



Two-inch cubes were placed in solutions containing 

 1 % hydrochloric and 1 % sulphuric acid, and allowed 

 to remain in it for 96 hours. As a result of this 1-031 % 

 by weight was lost, and a decided darkening in colour was 

 produced ; this value is rather high. 



Specific Gravity. 



The specific gravity of this stone is about 2-30, and 

 thus has a weight per cubic foot of approximately 1441bs., 

 a medium weight for a sandstone. 



Fire Test,* 



The stone, after being subjected to a temperature of 

 750° C. for 15 minutes was plunged suddenly into cold 

 water and was uninjured, no chipping at the edges, but 

 merely a deepening in colour due to further oxidation of 

 the iron contents. 



The above results, together with its observed mode 

 of weathering, point to the stone being c^uite a satisfactory 

 one for the purpose it is asked to serve in this building. 

 (4) Harcourt Granite. 



This has been used very extensively in Melbourne 

 and other parts of Victoria. It is distinctly handsome 

 when polished, though in this building being used in the 

 foundations it is not polished. 



This is a somewhat coarse-grained grey granite, which 

 is made up of quartz, felspar, and the black mica biotite, 

 the latter being in abundance and sufficiently fresh to show 



