Floods on the River Barwon. 115 



stream has to pass, and this 290 feet is so surrounded by 

 obstructions in the way of piles, iron rods, walings, braces, 

 stanchions, and chains, also a great bed of reeds, and several 

 dead trees, that I fail to see that it is equal in discharging 

 power to more than one half of the clear unobstructed 

 opening of 390 feet at the road bride. Thus the railway 

 bridge instead of double, affords only half the effective 

 tuaterway of the road bridge, which itself has proved not 

 quite large enough. In the experiments with the model, it 

 was observed that the heading up of the water at the road 

 bridge was always less than half that which occurred at the 

 railway, and that in this latter case the great fall in the 

 surface of the water took place, not under the bridge, but 

 between the south end of the bridge and the south-west 

 corner of Ha worth's Tannery, and just below the point 

 where the true constriction exists. 



In conclusion, I feel bound to raise my most earnest and 

 emphatic protest against the way in which the gentlemen 

 on the defence set aside scientific laws and formulae as 

 " mere theory," and insisted on practice being the only guide. 

 Now, Sir, what is this theory but the practical experience 

 of the best and wisest men that have ever given their 

 attention to the subject, systematised, verified, and adapted 

 to cases of ordinary professional work ? And what is practice 

 but simply one's own way of doing one's work, differing in 

 every individual case, which may be right or wrong, 

 scientific or crude, economical or extravagant, according to the 

 mental constitution, and amount of education possessed by 

 the engineer ? The popular idea that science is mere theory, 

 and unreliable when brought to the test — while practice, 

 ignorant, inconsistent, and unintelligible, as it too often is, is 

 the only guide to be followed, is a delusion leading to the 

 most deplorable results. 



k2 



