NEW SOUTH WALES TIMBERS. 631 



The Brinell ball test, at present very largely used for testing 

 the hardness of metals, consisting of measuring the diameter of a 

 circular impression made under a definite pressure, and dividing 

 the pressure by the area of the indentation. In this case the 

 diameters were measured by a special micrometer ; the pressure 

 was 1,000 kilogrammes applied for two minutes, and the ball 

 was of hard steel, 20 m.m. diameter. 



The cone press ire test, carried out by means of the Brinell 

 apparatus, substituting for the steel ball a right-angled cone, which 

 latter is forced into the timber with a definite pressure, and the 

 depth of penetration measured by means of a special apparatus 

 made for these tests by Messrs. Amsler Laffon & Son, Schaffhausen, 

 Switzerland. 



The cross-compression test showed that grey gum from the 

 South Coast was the hardest, and white stringy bark the softest. 

 No one timber showed a decided advantage over another. Iron- 

 bark did not give the results expected, whereas turpentine ex- 

 ceeded all expectations. 



In the other tests grey gum and ironbark were the best, fol- 

 lowed by turpentine ; South Coast tallow-wood was tenth. South 

 Coast blackbutt eleventh, North Coast blackbutt sixteenth, and 

 white stringy bark last. 



The hardness of New South Wales timbers can be best realised 

 by a careful study of the numerous tables and diagrams con- 

 tained in this paper. 



5.— MODERN LIGHTHOUSE ILLUMINATION. 

 By JAMES SHIRRA, Engineer Surveyor, Department of Navigation, Sydney. 



(abstract) 



In these days, or rather nights, of artificial illumination we are 

 apt to forget how very modern all such amenities of civilisation 

 are. Oil lamps are of unknown antiquity, but only in very recent 

 times have they been scientifically constructed ; but a large Doty 

 Argand lamp, or its modification by Douglass, which may burn 

 a gallon and a- half oil per hour, gives a very great heat as well as 

 a fair light, and is difficult to manage. Gas or electricity, where 

 available, are more manageable, but require much machinery. 

 The incandescent petroleum-vapour lamp, where kerosene vapour 

 is burnt under a Welsbach mantle, is the real modern lighthouse 

 illuminant, and nearly all new — and many old — lighthouses are 

 being fitted with it. Acetylene gas, made by the action of carbide 

 of calcium on water, is a promising lighthouse illuminant, but is 

 not without disadvantages. When compressed into receivers filled 



