TIMBER BRIDGE CONSTRUCTION IN N.S.W. XIX. 
he had made no extra allowance in the railway bridge, and for a 
very good reason. The material for the original bridge had 
frequently to bear long road cartage, but the train brought the 
renewal mentioned to the spot at a very low rate. 
Mr. ALLAN, in replying, said that the exhibiting by Mr. Deane 
of the plans of the truss bridges to be erected on the Narrabri- 
Moree railway line, clearly showed how economically Australian 
hardwoods could be utilised for railway structures. Mr. Burge, 
whilst agreeing that in any case a saving in favour of the 
timber bridge at Wagga Wagga had been shown, thought the 
_ timber structure should have been compared with an imported 
: metal bridge. He could not follow Mr. Burge in this, the iron- 
work in the timber bridge costing £490 was not only manufactured 
but rolled in the Colony, the iron bridge was also stipulated 
to be manufactured in the Colony, therefore the estimated 
actual cost to the country, irrespective of colonial rate of wage, 
duty, or other similar contributing causes was, Mr, Allan held, 
the only basis on which a comparison could be made. He 
could not with confidence make any remarks on Mr. Burge’s 
comparison, as to the relative financial results of small concrete 
and timber railway culverts, without looking into the question. 
The experiences of Mr. Smail as to the difficulty of renewing tim- 
ber in the old type of trusses agreed with his conclusions. The 
complex character of the theoretical investigation of the strength 
of a column, carrying different loads throughout its length, 
remarked upon by Mr. Barraclough, was the reason of reference 
being made to the case in the hope that information might be 
given by some of the members on the question, The Author's 
practical method of treating the subject was based on actual 
experiment as to the buckling strength of ironbark columns of 
different ratios of length to diameter. 
Mr. Statham’s opinion that the using of flitch pieces permitted 
of matured timber being utilised, thereby ensuring cheap supply 
and increased durability, is of considerable importance, the 
benefit of which has been recognised in the new type of trusses. 
