BY HENRY C. RICHARDS, M.SC. 205 



up well in contrast to the milky-white felspar and colour- 

 less quartz. It has proved its stability as a building stone, 

 -and a notable example of its use and weathering is to be 

 seen in the Equitable Buildings, Collins Street, Melbourne. 

 It is a stone that works with ease in all directions, can be 

 obtained in very large blocks, and quarries well ; the quarries 

 being in close proximity to the railway line at Harcourt, 

 it can be delivered in Melbourne at a very reasonable rate. 

 The local granite from Enoggera must be regarded 

 as an inferior stone in many ways, but owing to its con- 

 taining hornblende, as far as strength is concerned it 

 probably surpasses the Harcourt material, but this mineral 

 also greatly increases the cost of working. The Enoggera 

 stone is rather fine in texture, has not the same relief when 

 polished, and is liable to contain crystals of pyrites and 

 vughs of calcite. These two latter minerals weather 

 Tapidly, especially the former, which becomes oxidised, 

 and a dirty brown patch is formed. This phenomenon 

 may be well seen in many of the stones used in the base 

 of the Lands Office. Compression tests on three-inch 

 ■cubes of Harcourt Granite have given the following results : 



Stone. Lbs. per sq. inch. Tons per sq. foot. 



JIarcourt granite .. .. .. 11,444 736 



JIarcourt granite 11,333 729 



Being an igneous rock it is almost impervious, and all 

 its minerals are of a very stable nature, there being no 

 ■carbonates or sulphides, while the black mica is found to 

 stand weathering excellently. The climatic conditions 

 likely to affect the stone are those of extreme temperature, 

 but in this city no fear need be anticipated on that score. 



(6) FooTSCRAY Basalt. 



This is the familiar bluestone used in Melbourne for 

 many varied purposes, of which the uses for building stones, 

 copying stones, pitchers, and road metal, are the chief 

 ones. It is a dark compact basalt which works easily 

 and as a result of its proximity to the city in buitable masses 

 is cheap. 



Owing to its igneous nature and its chemical con- 

 stitution, it is an excellent weathering material, bub buildings 

 of this stone alone are objected to on account of its 

 sombreness, though for bulk stores and gaol structures 

 it gives an air of great solidity. It is chiefly used as a 



