NEW ZEALAND WOODS. 179 



plied, and to the remainder 56 lbs. At the end of the second hour the 

 examination was repeated, and was followed by a similar addition of 

 weight, and so on till the piece was broken. 



To the specimens of larger scantling, viz. 1^ by 3 inches, 8 cwt. 

 was applied in the first place, and 56 lbs. added at the end of each 

 hour. 



An arrangement was made by which the amount of deflection pro- 

 duced by the weight applied was multiplied on a dial. By this means 

 a difference in deflection of -^ of an inch, or a deterioration of the 

 elasticity to the same amount, was rendered apparent. 



Attempts were made by various means to determine in each case the 

 position of the neutral axis, but without any reliable result being ob- 

 tained. In the majority of cases the neutral axis appeared to be some- 

 what below the centre line, and, within a confined limit as to weight 

 applied, to be stationary. In some woods however the neutral axis 

 was situated far above the centre. No. 5 of the Table, for instance, 

 bent like a rope round the point when the strain was applied; the 

 fibres on the convex side elongating with readiness. In every case the 

 addition of weight beyond a certain point altered sensibly the position 

 of this axis. On the whole the results obtained were so anomalous as 

 to induce me to abandon for the present the investigation of this por- 

 tion. of the subject. 



Of the woods tried, I consider there are but six (Nos. 3, 6, 7, 8, 9, 

 12, of the accompanying Table) which the experiments have shown to 

 be eligible for the purpose of resisting cross strains. As I am unac- 

 quainted with New Zealand woods, it is possible that even some of 

 those which these experiments have shown to possess the necessary 

 quality may not be procurable in size or quantity sufficient for building 

 purposes. Though those woods only which I have mentioned appear, 

 as far as I have been able to test them, to be suitable for resisting cross 

 strains, it is possible that some of the others may possess the property 

 of resisting compression as well as tension in the direction of their 

 fibres. They may, for instance, prove serviceable as piles, struts, or 

 tie-beams ; they may be able to resist the action of moisture and even 

 of sea-water. To ascertain the latter point, I have caused to be placed 

 in a perforated case specimens of the woods numbered 3, 4, 5, 6, 7, 8, 

 9, 12, 13, 15, and have had them sunk in the harbour near Fort Mac- 

 quarrie. 



