Page:Timber and Timber Trees, Native and Foreign.djvu/74

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54
TIMBER AND TIMBER TREES.
[CHAP.

In the specimens marked 1 to 6, the greatest strength was possessed by the piece taken from close to the centre of the log, which comprised the oldest and densest annual layers, while No. 6, which was farthest removed from it, and contained the most recently perfected duramen, proved to be the weakest, the respective breaking weights showing a difference of nearly 2 per cent.

Turning to the specimens marked 1′ to 6′, taken from the other side of the tree, we find a similar result as regards the inner and the outer layers, the greatest strength being again near to the centre of the tree; No. 5', however, bearing the next greatest strain. The pieces Nos. 2', 3', 4', and 6', each broke as the weight of the scale was applied, and are therefore of little value.

We may gather, however, from the trial, that from the centre to the circumference of this tree there was clearly a diminution of strength, which, although not quite proportionate to the decrease observed in the specific gravity of the several pieces, is yet in some degree approximate to it. I infer from this that the tree had not reached maturity when it was cut down, and that it was still in the prime of life. Had it been otherwise, we should have expected, when viewed by the light of other experiments, to find that the point of density and greatest strength would lie in the piece marked 4, or even farther removed from the centre.

There can be very little doubt that the wood of this tree, if used in its greatest bulk, or in any large scantlings, would have been found to possess fully the average strength of Oak timber, and that it was only weak in certain parts, as discovered on trial when cut into strips of 2 inches square. There still remains,