XVIII. DISCUSSION. 
on the column in question would make the matter a very complex 
affair. 
Mr. SrarHam remarked that there were a great many points in 
favour of Mr. Allan’s design in comparison with the old ones. 
It was a great defect that so many timbers were in contact in 
the chord, the damp got into the joints and caused great damage, 
which practically meant the renewal of the chord, and when the 
chord was done the bridge was practically done, but in this new 
design there were a great many improvements. The new method 
of making up the top chord of smaller scantlings utilised the best 
part of the timber. Such bridges as these should last 30 years 
which was the life of the best ones. 
Mr. Simpson—One thing that struck him was the comparison 
of prices. It was not a fair thing to compare colonial iron work 
with timber work, because the former is not of the cheapest kind. 
He assumed that the price of timber work included the painting, 
at 4s. per cubic foot, and that of the iron was at 23s. per ton, 
erected. Then taking Mr. Allan’s margin of safety, he found 
that for the 90ft. span the price of steel work was 7s. per foot of 
the top chord, as against 3s. for timber, so that these comparative 
prices were in favour of timber. Personally, he would prefer to 
deal with a steel or iron structure. As regards the extra prices 
and renewals, a certain proportion of this timber work had to be 
renewed in a few years, and it seemed the renewal prices had == 
been calculated upon the same basis as for the original, which 
was quite incorrect. A timber bridge requires constant inspec- 
tion, which would add greatly to the cost, and for these reasons 
he thought he would prefer larger works to be of steel instead 
of timber. . 
Mr. Borer, in explanation, said that the Chairman had 
remarked upon the cost of renewals being taken as the same as 
the original provision of the timber, but Mr. Allan had provided 
for the extra cost. He had put down the cost of the renewal of 
planking at £220 as against £180 original cost, and of the rest 
£950 as against £630. As to his own (Mr. Burge’s) comparison; — 
Careeth a. poe 
Sos eae 
