xi. PERCY ALLAN. 
suspended from the chords by sixteen beam hangers 1} inches 
diameter passing on either side of the flitches of chords. 
The author is of opinion that for timber railway bridges of 
large span, the floor system above described offers some advantages, 
inasmuch as shock from trains would be reduced by the lateral 
strut and distributing blocks acting as a cushion ; whilst the beam 
hangers being so short a large allowance could economically be 
made for dynamic action, which: action would be materially 
lessened by the time the main suspension rods were reached. 
In connection with the construction of timber bridges, the 
financial aspect of the question is of the utmost importance. 
Like all engineers, the author would prefer (if economy had not 
to be considered) to construct metal bridges, but in a new Colony 
where the trend of the traffic is likely to be diverted by many 
circumstances, difficult, if not impossible, to anticipate, it would 
seem preferable in such localities to construct timber structures 
with a small capital outlay, rather than spend large sums on 
works of a more permanent character. 
For many years there has been a disinclination in this Colony 
to build other than permanent traffic bridges out of loan funds, 
yet as harbour works and railway works, in which timber struc- 
tures, sleepers, fencing, etc., represent no inconsiderable portion, 
are built out of loan funds, the author submits there is no reason 
why traffic bridges should not also be constructed out of borrowed 
capital, provided it can be shown, first, that they are more 
economical not only in prime cost but in annual charge, and 
secondly, that provision be made for their renewal or repayment 
out of revenue. 
It may be urged in these days of cheap steel, that it is against 
the practice of other parts of the world to construct timber 
bridges, but in what other country could be found timber with a 
tensile strength of 8 tons per square inch, a crushing strength of 
47 tons per square inch, and a shearing strength along the grain 
of 1 ton per square inch ; or bridges totally unprotected from the 
