MAGAZINE OF SCIENCE AND ART. 
261 
REPORT OF EXPERIMENTS 
NEW ZEALAND WOODS. 
ON 
The following woods from New' Zealand 
to determine in each case the position of 
the neutral axis, but without any reliable 
result. In the majority of cases the neutral 
have been tested as to their capability of a ^ 3 appeared to be somewhat below the 
bearing pressure applied to the centre, 
while supported at the tw'o extremities:— 
No. Native Name. Scientific Name. 
Dammara Australis. 
Podocarpus. 
Metrosideros Kohusta. 
Dacrydium Cupressinam. 
Dicera Dentata. 
Podocarpus Ferruginea. 
Septospernum Scoparium. 
. . Knightia Excelsa. 
.. Laurus Kohe Kohe. 
.. Suttonia Australis. 
.. Nesodaphne Tawa. 
. . Podocarpus Excelsa. 
.. Jeiospernum. 
.. Dacrydium. 
woods were sent from New 
1. Kauri 
2. Totara 
3. Kata 
4. Eimu 
5. Hinan 
6. Miro 
7. Manulra, orTea 
Tree 
8 . Mangeia. 
9. Eewa Kewa . . 
10. Kohe Kohe .. 
11. Mapan 
12. Tawa 
13. Tawari. 
14. Kafiika 
15. Towhai 
10. Matia 
The above 
Zealand, having been selected and for¬ 
warded to this colony for the purpose of 
experiment, at the request of the Governor- 
General. Of the first four on the list three 
specimens were sent, of the last three ono 
specimen, and of the remainder two. 
The first experiment was made with the 
view of obtaining a rough approximation 
to the value of each description of wood. 
The second was conducted with more care. 
Those woods, of which specimens could not 
g 
be obtained of greater scantling than 1 — 
inches square, were subjected, in the first 
place, to a ^strain of three cwt. applied at 
the centre point. After an hour the weight 
was removed, and the effect of the pressure 
or the elasticity, if any, noted. To those 
woods, which the first trial had indicated 
to be superior, an additional 28lbs. was 
now applied, and to the remainder 561bs. 
At the end of the second hour the exami¬ 
nation was repeated, and was followed by 
a similar addition of weight, and so on till 
the piece was broken. 
To the specimens of large scantling, viz., 
1^+3 inches, 8 cwt. was applied in 
first place, and 56 lbs. added at the end of 
each hour. 
An arrangement was made by which the 
amount of deflection produced by the 
weight applied was multiplied on a dial. 
By this means a difference in deflection of 
l-20th of an inch was rendered apparent. 
Attempts were made by various means 
centre line, and within certain limits as to 
weight applied, to be stationary. In somo 
woods, however, it was situated far abover 
the centre. No. 5 of the table, for instance, 
bent like a rope round the point where the 
strain was applied, the fibres on the convex 
side elongating with readiness. In every 
case the addition of weight beyond a certain 
point sensibly altered the position of this 
axis. On the whole the results were so 
anomalous as to induce me to abandon for 
the present the investigation of this portion 
of the subject. 
Of the woods tried, I consider there are 
but six (Nos. 3, 6, 7, S, 9, 12, of the 
accompanying table) which the experi¬ 
ments have shown suitable for sustaining 
strains. As 1 have no knowledge of 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. Of the 
woods proved eligible some may be capable 
of resisting tension and compression in the 
direction of their fibres, and may be ser¬ 
viceable as piles, struts, or tie beams. 
The value of S, that is the constant re¬ 
presenting the strain any particular wood 
can bear without fracture has been calcu¬ 
lated and given in the table for each 
specimen. 
I have not considered it necessary to 
calculate in any case the value of E, that 
is the constant representing the elasticity 
of the wood ; but the results in the accom¬ 
panying table are sufficient for this purpose 
should the elasticity of any particular spe¬ 
cimen be required. 
To decide with confidence on the value 
of those New Zealand woods, which have 
exhibited desirable properties, further trials 
would be necessary. Nos. 3, 6, 7, 8, 9, 12, 
of the table might, with advantage, be sub¬ 
mitted to further tests, and for this pur¬ 
pose specimens 5 feet “ 6 ” long and 
3 “-J-2" scantling would be preferable. 
The practical application of the values 
of E and S has been explained in the 
paper on the woods of New South Wales 
presented to the Society. 
E. W. Ward, Captain, 
Royal Engineers,. 
