95

stapled. Flour in bags of from 100 to 200 lbs.

I have the honor to be,
Sir,
Your most obedt. servant,

ALFRED ECCLES,
Honorary Secretary.

His Honor the Superintendent,
Hawke’s Bay.

NEW ZEALAND EXHIBITION, 1865.

The following amended and further instructions have been drawn up for the information of Local Committees and Exhibitors, and it is particularly requested that when possible they may be strictly adhered to:

Experiments on the Strength of Materials, &c.

The original intention of the Commissioners was to follow up the train of experiments instituted by Capt. Fowke, R.E., on various samples of colonial timbers in the Paris Exhibition of 1855. These experiments were from necessity made on very short scantlings, and the samples experimented upon were supported at each end. The results obtained were most satisfactory so far as the ultimate strength of the samples was concerned, but the form of the specimens and the manner in which they were supported rendered the measure of elasticity not quite so satisfactory, that property being better ascertained from more slender samples fixed at one end only... No trials were made at Paris of the tensile strength of timber in the direction of the fibre, and no trials appear ever to have been made on the tensile strength transverse to fibre, and yet it appears that both these sets of experiments would give very useful practical information. It has consequently been considered by the Associate Committee of Consulting Engineers that the experiments on timbers should be extended to embrace the following subjects:

1. Ultimate transverse strength
2. Elasticity (imperfectly)
3. Crushing strain in line of fibre
4. Crushing strain transverse to fibre
5. Elasticity, more delicately
6. Tensile strain in line of fibre
7. Tensile strain transverse to fibre

In order that these experiments may give satisfactory results, it is desirable that each should be repeated at least three times to eliminate the effect of accidental flaws, &c.; the number and sizes of the samples required for this purpose are given below, all scantlings being given a little full to allow the samples to be finally dressed accurately to size shortly before they are to be experimented upon.

As bearing on the question of the durability of different timbers in various works of construction, samples which have been a known length of time exposed in trying situations, whether as piles in marine works, as piles in fresh water, or as house piles, or fence posts, &c., both in dry and marshy soils, whether sound or partially destroyed, would be very valuable. In cases where different varieties of timber have been employed in the same work, and have consequently been equally exposed in precisely similar circumstances, samples of each kind should, if possible, be furnished, as affording incontestable evidence of their comparative durability.

In the case of lime and cement stones, the Associate Committee propose to submit the various samples to certain practical tests, the results of which, when tabulated, will give, if not more information than the chemical analysis, yet information in a more practical form, and one which will probably be more generally understood.

With this view it is desirable that a sufficient quantity of each sample be forwarded, as explained below.

Building Stones.

It is desirable that three cubes of not less than eight inches of all building stones should be exhibited, each cube showing the various kinds of workmanship of which the stone is capable, and which are generally put on the stone; one side, when practicable, being polished.

Sufficiently large samples of all lime and cement-stones should be sent to admit of a portion being burned and slacked, and practically experimented upon. It is desirable that enough should be furnished to allow at least a quarter bushel of slacked lime being prepared in each case.

With each stone the Commissioners desire to be furnished with the following information:

1. Name of the country or colony, and province or district, and quarry from which the stone was obtained.
2. The aboriginal and local name.
3. A short description of the formation in which the stone occurs; its abundance or scarcity; the nature of the country; its proximity to the coast or harbour, navigable river, railway, road, or other facility for transport; the purposes for which it is applied in the country, and the estimation in which it is held for strength and facility of working; its durability under various circumstances of exposure, &c.; the names of any public or other buildings in which it has been used, and for what purpose, their date of erection, and the present condition of the stone therein; the cost in the colony or country per foot cube at the quarry, and on board ship at the nearest available port; the size of which it is most easily, and the extreme size at