46 



ihaiiy instances, and as one block is attiiolied, dry-rot spreads througtiout those 

 ai'ijucent. A samjile block showing this decay is forwarded herewith." Again, 

 jirtfje 10: "My experience of Spotted Gnm leads me to advise that the use of 

 tiiis wood be discouttnued." 



The same gentleman has also courteously replied to our schedule of ques- 

 tions (Appendix At), in which he still holds to his adverse opinion. So strong 

 a condemnation, coming from such an important source, requires our careful 

 consideration. We find, however, after examining over 200 wood-blocks, which 

 V ere recently removed from various streets in Sydney, about 150 of which 

 ;were presented (labelled as to class) to the Department of Forests, by the 

 f-ity Surveyor, that the names given on the labels are in some instances 

 incorrect. 



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 ofBcial report by the City Surveyor to the 

 ;T'nder Secretary tor 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 

 fie inferred from figures thus obtained. We are of opinion that, owing to the 

 • ouditions under which the city paving-blocks were laid, the tests are of little 

 Talue. To begin with, it is almost impossible to obtain blocks exactly 6 inches 

 <leep. This is recognised from the fact that it is usual to allow contractors a 

 ^'ariation of J^ of an inch when cutting, allowance being made for the set of 

 "i I'eth of the saw, and other circumstances it would be diflicult to control. After 

 the blocks are laid, the wear for some time will depend on the merits of the 

 top-dres.?ing (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 

 . fuid similar conditions are of little value. 



The Ad\'antaoes and Disadvantages to the Use of Spotted Gum 



consideked. 



(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. 



C. 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 six- 

 teen 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 

 nound. (Dingo Creek, Belbowrle, near Wingham.) The life of rails of a 

 <-hock-and-]og fence is given at tliirty-flve years. Several witnesses give the 

 life of rails at twenty years, others thirty years, other "fences" (? rails) at 

 jforty and more. One correspondent gives the lives of " posts " at forty years. 



, Shiugles are stated to last thirty years. Turning to shipbuilding, the plank- 

 ing, beams, &c., of a pilot steamer, after nineteen years' wear, were stated to 

 tte " as sound as ever." At the London Exhibition of 1802 a piece of timber 



t Not reproduced. 



