SCIENCE SIFTINGS

New Zealand Tablet, Volume XLVI, Issue 18, 1 May 1919, Page 46

SCIENCE SIFTINGS

By "Volt."

• The Wood Borer. An interesting paper on the subject of the susceptibility of New Zealand timbers to the attacks of the borer was read by Mr. R. Speight at a meeting some time ago of the Canterbury Philosophical Institute. Mr. Speight stated that his observations had been made from a fairly complete series of New Zealand timbers which were collected principally in the early days by Dr. von Haast, but added to by Captain Hutton. The timbers were in the Canterbury Museum and most of them had come from the forests that once grew in the province of Canterbury, notably those on Banks Peninsula ; but representatives had been obtained from other parts of New Zealand, the total number exceeding 150. The museum had been exposed to the ravages of the borer, and the timbers were in a part in close contact with the wood which was seriously affected and all were equally exposed to attack. Some of the timbers, said the lecturer, were immune, while others showed a varying proportion of affected specimens. It was frequently found that the sap was attacked while the heart wood was unaffected. This was especially the case with regard to the matai, commonly known as black pine. A considerable quantity of this timber had been used in the construction of the Museum, and the sap was almost universally affected while the heart had invariably escaped, and was now so hard that it was difficult to drill it. It was somewhat remarkable that specimens of kahikatea or white pine, which was always looked on as one of the most susceptible of timbers, had been but slightly affected, although it had been badly attacked where used in the construction of the Museum building. The only reason the lecturer could assign for this was the experience of builders, who stated that timber from trees grown on hillsides or river terraces had more resistent properties than that grown on swamp lands, and that timber cut in the winter had superior lasting power over that cut in summer. Continuing, the lecturer said, in view of the threatened shortage of local supplies of timber it was of importance that the utmost should be made of what we now had. A great source of waste was due to the ravages of the borer, which necessitated a considerable amount of timber being used in replacements. There was no doubt that this waste could be minimised by the adoption of methods of sterilisation in connection with building timbers. Some of these processes would not only prevent entirely the attacks of the borer but would prolong the life of the timber as well, and have no deleterious effect on human life. A thoroughly satisfactory method of treatment had been found to be the soaking of timber in petrol in which carbolic acid and camphor had been dissolved. This specific had been effective as far as the petrol penetrated into, the wood, and would therefore protect new timbers entirely. Both these substances would no doubt disappear from the wood in time, the former as a result of the action of water, since carbolic acid was slightly soluble in it and the latter owing to- its gradually passing off, as a vapor. It was possible that the substitution of naphthalene for the carbolic acid would to some extent obviate these slight objections.