ICO 
In some instances we find a badly-worn block labelled “ Spotted Gum,” which on examination 
proves to be some other timber ; and, again, some blocks which have worn well are Spotted Gum, although 
labelled otherwise. In other words, a general statement, whether of praise or condemnation, founded on 
data such as this, must be unreliable. 
We further observe that in an official report by the City Surveyor to the Under Secretary for 
Mines and Agriculture, the rate of wear per annum, in the Sydney streets, of Spotted Gum and other 
timbers is calculated to very small fractions of an inch, and certain conclusions are based upon or left to 
be inferred from figures thus obtained. We are of opinion that, owing to the conditions under which the 
city paving-blocks were laid, the tests are of little value. To begin with, it is almost impossible to obtain 
blocks exactly 6 inches deep. This is recognised from the fact that it is usual to allow contractors a 
variation of of an inch when cutting, allowance being made for the set of teeth of the saw, and other 
circumstances it would be difficult to control. After the blocks are laid, the wear for some time will 
depend on the merits of the top-dressing (which varies under climatic conditions), and the position of the 
blocks in the carriage-way, whether they are near the centre of the roadway where the traffic is heaviest, 
or near the kerbs where it is likely to be less. 
We are, therefore, of opinion that tests which do not fulfil accurately all and similar conditions are 
of little value. 
This Advantages and Disadvantages to the Use of Spotted Gum considered. 
(a) Advantages. 
The advantages stated by several persons are—- 
1. Durability. 
2. Strength, toughness, and elasticity. 
3. Capacity for bending. 
4. Lightness. 
5. Easy working. 
6. Evenness of quality. 
7. Large sizes readily obtainable. 
8. Comparative freedom from pipe. 
1. Durability. 
It has a life of over thirty years in the Singleton Railway bridge A similar life is stated for slabs 
in barns and slab-houses on the Berry Estate. 
For bridge decking the life is given variously up to thirteen, fifteen, and sixteen years. Another 
correspondent states its life as six and ten years in “bridge and culvert work.” 
The life of joists is given at twenty years, and of girders at twenty-five years. We were informed 
of a girder twenty-six years in a bridge, and still quite sound. (Dingo Creek, Belbowrie, near Wingham.) 
The life of rails of a chock-and-log fence is given at thirty-five years. Several witnesses give the life of 
rails at twenty years, others thirty years, other “ fences ” (? rails) at forty and more. One correspondent 
gives the lives of “ posts” at forty years. 
Shingles are stated to last thirty years. Turning to shipbuilding, the planking, beams, etc., of a 
pilot steamer, after nineteen years’ wear, were stated to be “as sound as ever.” At the London Exhibition 
of 18G2 a piece of timber was shown from the hull of the steamer “William the Fourth,” and properly 
certified. With the exception of some slight charring on the mere surface of the timber in the immediate 
vicinity of the boilers, the entire fabric of this vessel is as substantial and sound as when she was built in 
the year 1830 (thirty-one years’ wear). If the above statements as to the life of Spotted Gum be examined 
(and reference to the evidence will show that other instances of long life of the timber can be quoted), no 
doubt can remain that, under the circumstances alluded to, Spotted Gum is a very durable timber, in fact, 
that it is one of the most durable of our timbers for the purposes stated. 
2. Strength, Toughness, and Elasticity. 
We have already dealt with this in speaking of the fitness of Spotted Gum for eoachbuilders’ 
purposes, <fcc. 
