32 The Tay Bridge. 



1. That during heavy gales railway traffic should be 

 stopped on high bridges and exposed parts of the line. 



2. That the Tay Bridge fell under a gale of by no means 

 unprecedented severity owing to the weakness of the brac- 

 ing of its piers. 



3. That this bracing should have been about four times as 

 strong as it actually was made. 



4. That had the bracing been satisfactory the bridge 

 would have been in danger of overturning bodily under a 

 wind pressure less than has repeatedly been observed. 



5. That such overturning could be prevented by proper 

 anchorage, which anchorage did not exist in the structure as 

 built. 



It may be asked, How came so important a structure to 

 have been built in ignorance or defiance of the laws of 

 statics — laws which have been known and taught in univer- 

 sities and elsewhere for centuries ? and how came it that no 

 one detected the error during all the years that were occu- 

 pied in building it ? To these questions a positive answer 

 cannot be at present given. I strongly incline, however, to 

 the belief that the Tay Bridge is a conspicuous but by no 

 means solitary result of an imperfect system of education, 

 which ignores the necessity of accurate training in dyn- 

 amics on the part of those who enter the engineering pro- 

 fession. It is currently believed that a mysterious aptitude 

 gained by long acquaintance with professional matters is an 

 effective substitute for mathematical knowledge. The Tay 

 Bridge, probably, is only one of many instances proving that, 

 while ordinary practical experience, unaided by accurate 

 scientific knowledge, may suffice for the routine of daily 

 work, it is liable to fall into the most dangerous errors in 

 structures of special form, and under unusual conditions. 

 For the higher and more special class of engineering 

 problems we need scientifically educated men, not mere 

 empirics. 



With regard to the second part of the question — why the 

 error was not detected — it may be stated that, contrary to the 

 usual and excellent practice in the case of important struc- 

 tures, no details of the construction were made public in 

 the engineering journals or otherwise; and from its position 

 the bridge was not readily accessible to visitors. 



The evidence taken so far as to the accident shows that 

 the workmanship was far from being as perfect as is usually 



