Page 4 Advertisements Column 2

New Zealander, Volume 12, Issue 1116, 27 December 1856, Page 4

Native Name. No. 1. Kauri 2. Totara 3. Kata 4. Rimu 5. Hinau G. Miro 7. Manuka or Tea Tree 8. Mangaia 9. Rewa Kewa 10. Kobe Kobe 11. Mapau 12. Tawa 13. Tawiri 14. Kaliika 15. Towhai IG. Matai Scientific Name. Dammara Australis Podocarpus Metrosicleros Robusta Dacrydium Cuprossinum Dicera Dcntata Podocarpus Ferruginea Leptospermum Scoparium Knightia Excelsa Laurus Kobe Kobe Suttonia Australis Ncsodapbue Tawa Podocarpus Excelsa Leiospermum Dacrydium The above Woods were sent rrom x.c. Zealand, having been selected and forwarded to this Colony at the request of the Governor General, for the purpose of experiment. Of the first four on the list, three specimens were sent ; of the last three, one specimen ; and of the remainder, two. The first experiment was made with a 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 spccimems could not he obtained of greater scantling than 1 9-10ths inches square were subjected in the first place to a strain of 3 cwt., applied at the centre point. After an hour, the weight was removed and tire eftect of the pressure on the elasticity —if any —was noted. To those woods which the first trial had' indicated to be superior, an additional 2<S lbs. was now applied, and to the remainder, 5G lbs. At the end of the second hour the examination was repeated and was followed by a similar addition of weight, and so on till the piece was broken. To the specimens of larger scantling, viz., 1 9-10ths by 3 inches, 8 cwt. was applied in the first place, and 5G ll>s. 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, or a deterioration of the elasticity to the same amount, was rendered apparent. Attempts were made by various means to determine in each case the position of the neutral axis, but without any reliable result being obtained. In the majority of cases, the neutral axis appeared to be somewhat below the centre line, and, within a confined limit as to weight applied, to be stationary. In some woods, however, the neutral axis was situated far above the centre. No. sof the Table, lor instance, bent like a rope round the point when the strain was applied ; the fibres on the convex side elongating with readiness. In every case, the addition of weight beyond a, certain point altered sensibly the position of this axis. On the whole the results obtained 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, G, 7, 8, 9, 12 of the accompanying table) which the experiments have shewn to be eligible for the purpose of resisting cross strains. As lam unacquainted with New Zealand woods, it is possible that even some of those which these experiments have shewn to possess the necessary quality may not be procurable in size or quantity sufficient for building purposes. Though those woods only which I have mentioned appear, as far as I have been able to test them, to be suitable for resisting cross strains, it is possible that some of the others may possess the property of resisting compression as well as tension in the direction of their fibres. They may, for instance, prove serviceable as piles, struts, or tie beams ; they may be able to resist the action of moisture and even of sea water. To ascertain the latter point, I have caused to be placed in a perforated case specimens of the woods numbered 3, 4, 5, fi, 7, 8, 9, 12, 13, 10, and have had them sunk in the harbour near Fort Macquarrie. The value of S, that is the constant representing the strain any particular wood can hear without fracture, is calculated for each specimen. As a means for comparison it may bo stated that the value of S in the following known woods has been stated by Harlow to be as follows : Superior English Oak, S Ash 2037 E] m 1031 to 120G ]ii rc .p 1820 to 2037 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 given in the accompanying table are sufficient for this purpose, should the elasticity of any particular specimen be required. To decide with confidence on the value of those New Zealand woods which have exhibited desirable properties, further trials would bo necessary. At present I would suggest that other specimens of Nos. 3, G, 7, 8, 9, 12, of the table, say four of each kind, in length not under 5 feet 0 Inches and 3 inches by 2 In scantling, be obtained and he submitted to further tests. E. W. WARD, Gaft. R. Engineers. Colonial Secretary’s Office, Auckland, December 20th, 1856. HIS Excellency the Governor has been pleased to appoint 11. R. Aubrey, Esq., to be Postmaster at Wangarei. Mr. Geo, Jenkins to be Postmaster at Waiuku. Mr. John Hall to bo Deputy Postmaster at Otahuhu. Mr. Thomas Scott to be Deputy Postmaster at Mahurangi. By His Excellency’s command, E. W. Stafford, PRINTING. Colonial Secretary’s Office, Auckland, Dec. 20th, 1850. TENDERS will be received at the Native Secretary’s office, until noon of Saturday, the 24th of January next, from persons desirous to contract for printing the Maori Messenger for the 12 months commencing the Ist January, 1857. Security will be required for the due perfornfance of the contract, and the Tender should be accompanied by a notification of the consent of two parties who may be proposed as sureties. Further particulars may be obtained on application at this office. , By his Excellency’s command, E. W. Stafford.