Page:Timber and Timber Trees, Native and Foreign.djvu/214

194 a state of decay even while the outer portions are in full vigour. A tree under these conditions, the inner portions comparatively dry, and the outer full of sap, shipped at once to a hot climate like that of India, or to such a variable one as that of England, very naturally bursts from unequal shrinkage, being also exposed to very great changes of temperature. To obviate this peculiarity and apparent defect, let the Jarrah be fallen when the sap is at the lowest ebb, and hitched as previously suggested."

I have seen it stated in some correspondence from Western Australia that a specimen of Jarrah timber has been chemically examined by Professor Frankland, with the view to ascertain whether there is any peculiar acid or other substance present in it calculated to resist the attacks of the Teredo navalis. It does not appear, however, that anything of the kind has been found which could be credited with the effect referred to. It is believed by the Professor that the singular immunity from attack which this wood enjoys is due either to the odour or taste it possesses. These, though by no means remarkable or repugnant to the human senses, are probably strongly so to the Teredo navalis.