AGATHIS AUSTRALIS. 147 
Tensile Strength.—(Scantling, 2in. x 2in. x 30in.) 
j Breaking Weight in 
Relative Strength. Laaspes ote 
Ib, per sq. in. 
Pitch-pine it — . ‘616 ts 4,666 
KKAURI bes Bu “- *600 nie 4,543 
Russian larch _— As 1P4 "555 ae 4,203 
Riga fir Pr t. thy 535 Fe 4,051 
Canada spruce fe As <2 520 PA 3,934 
Dantzic fir Er os ate "427 ae 3231 
Canada red-pine... on = "357 se 2,705 
Canada yellow-pine... o =, 267 aus 2,027 
It will be seen from the above that kauri is excelled in transverse strength 
by the American pitch-pine and Dantzic fir—the former a timber not suitable for 
general building purposes; while the superiority of Dantzic fir is very slight, and 
it is decidedly inferior in tensile strength as well as in durability when exposed. 
| Special experiments made by Mr. Laslett to determine the relative strength 
of pieces taken from different parts of the same tree show that sections taken 
from butt lengths give the highest results, and that specimens taken from the 
latest-matured portions of the trunk were superior to those taken from the 
centre: this portion of the trunk corresponds to the ‘‘ white kauri’’ of Mr. 
Bartley, so that his conclusions with regard to its great strength are amply 
corroborated. The greatest tensile strength was exhibited by specimens taken 
from the central portion of the trunk, the position in which the greatest cohesion 
of the fibres might fairly be expected: in one set of experiments, however, the 
highest results both for transverse and tensile strength alike were obtained from 
specimens taken from the lately-matured wood. The specific gravity of the 
specimens tested by Mr. Laslett ranged from *498 to 595. In Mr. Balfour’s 
specimens 1t was much higher, +575 to *7oo. As Mr. Laslett’s specimens were 
tested in England they must have been well seasoned, which, doubtless, 
accounts for the discrepancy. 
There is, however, some difference between the results as to transverse 
strength obtained by Mr. Balfour from twelve specimens, and by Mr. Blair from 
thirty specimens: the former gives the breaking weight as 165’5o0lb., the latter 
as 137'17lb.* No details are given respecting Mr. Blair’s experiments, but 
Balfour’s conclusions make a close approximation to those obtained by Laslett. 
Some difference of opinion exists respecting the relative strength of kauri 
and other native pines. Although not equal to matai (Podocarpus spicata) and 
miro (P. ferruginea), it is, I think, superior to rimu (Dacrydium cupresssinum), 
kahikatea (Podocarpus dacrydioides), and totara (P. totava). As there is, however, 
a diversity of opinion on the subject, I append the mean breaking weight as 
stated by Balfour and Blair respectively :—- 
Balfour: Blair: 
No. of Breaking No. of Breaking 
Specimens. Weight, Specimens. Weight. 
Miro yy ie A i oar to Eon AAD 7 fa P20 Tee 
Matai iz ae Teo Bate LOO, 3 2a i. TOB'ON, 
KAuRI it “A! Tee 3. GUOS hee 8 <7 Bd onan  DSST A, 
Rimu oat ie Te SHORE By: 25 anc BTSA. , 
Kahikatea}+  ... aA, Io ¥ | 6F367;, <.. A Ae. 2666", 
Totara ane Me Be SS 368), “Ag TO ce, “hore, 
It is very desirable that a more extended series of tests should be made with 
all New Zealand timbers. 
* Blair: Building Materials of Otago, pp. 213-226. 
+ Excluding one specimen the identification of which appears doubtful. 
