332 



tances, AB, AC, and AD, are, respectively, 2061, 2125, and 

 24*25 in. A vertical support, HIv, rests on the table and 

 carries a knife-edge which can fit into any one of the nicks, 

 B, C, or D, and its height can be finely adjusted by the screw 

 L. When the specimen is placed on the table ready for test- 

 ing, this apparatus is placed alongside and parallel to it. 

 An electric battery is connected up to F and also to a bind- 

 ing screw attached to the castiron plate that is to crush into 

 the specimen. In the circuit is an electric bell. The knife- 

 edge supported by HK is then placed in the nick B, and the 

 height of the arm adjusted until E makes contact with the 

 underside of the castiron plate. As soon as contact is made 

 the bell rings, and the position can be adjusted very accu- 

 rately. Then the knife-edge is moved out until it rests in 

 the nick C. This lowers E exactly 3 per cent, of its original 

 height, whatever that may have been. The machine is now 

 set to work until the plate crushes down so as to again, make 

 contact with E, when the bell rings and the record is taken. 

 HK is then slid back till the knife-edge rests in the nick D, 

 and this lowers E exactly 15 per cent, of its original height. 

 Crushing again proceeds until contact is made once more and 

 the bell again rings. 



The results of the experiments so far made are given in 

 the tables that follow. For purposes of comparison the ave- 

 rage results of tests upon American Oak are given at the 

 bottom of each table, quoted from Professor Johnson's work 

 on "Materials of Construction." 



The experiments made are not sufficiently numerous to 

 enable fair general average values of the strengths to be de- 

 duced, but are given as the first instalment of what it is hoped 

 to make a much more complete series of tests, to be carried 

 out as opportunity offers. It is of obvious importance that 

 we should have as complete a knowledge as possible of the 

 properties of our local timber in order to decide upon what 

 trees to grow for the extensive schemes of replanting forest 

 trees that must be undertaken in the future. The speci- 

 mens of the Pink Gum f Eucalyptus fasciculosa) that have 

 been sent to me are magnificent timber, and, so far as I 

 know, no other tests have been made upon this species. In 

 every form of test it gave splendid results, and the timber 

 is remarkably dense and uniform. The specimens of Sugar 

 Gum, taken from matured forest trees, also gave very fine 

 results, although the timber is not of such a uniform tex- 

 ture as the Pink Gum. Tests were made of this timber from 

 trees fourteen and twenty-nine years old, and although the 

 results were not so good as those from the mature tree they 



