 When therefore in 1868 Captain Eads was ready, as chief promoter as well as chief engineer, to begin the work of constructing the great bridge over the Mississippi River at St Louis, he very naturally tendered the position of chief assistant engineer to Colonel Flad.As the duties of the latter, as member of the Board of Water Commissioners, did not require all his time, this opportunity to take part in this most interesting and important work was gladly accepted, and he retained his connection with it until its completion in 1874.Some of the boldest features of this great enterprise, such as the method of erection without falsework, were due to Colonel Flad.