The series of communications on iron bridge failures in the October 1981 issue of Technology and Culture (22:846-50) is curious in that it pits several humanists against one another in a debate over numbers. To an engineer, exactly how many railway bridges failed in the 19th century is not so important as the fact that failures did occur. The collapse of a single bridge of a relatively new material or design should have been enough to make contemporary engineers and their customers, the railroads, reflect on the new technology. The repeated collapses of iron railway bridges could only have cast suspicion on the adequacy of technological understanding and raised doubts within and without the developing railroad industry. And they did. As Cyril Stanley Smith notes in the chapter on fracture in A History of Metallography: The Development of Ideas on the Structure of Metals before 1890 (Chicago, 1960), the introduction of the railroad train, like that of the stagecoach before it, was fraught with repeated failures of iron axles. This, along with the failure of the iron railway bridges that were being built in large numbers at the time, prompted Queen Victoria in 1847 to appoint a commission to look into the use of iron. As quoted by Smith (pp. 122-23), Her Royal Highness charged that the commission should endeavour to ascertain such principles and form such rules as may enable the Engineer and Mechanic, in their respective spheres, to apply the Metal with confidence, and shall illustrate by theory and experiment the action which takes place under varying circumstances in Iron Railway Bridges which have been constructed. The commission's report, published in 1849, promulgated a misguided idea about the fatigue of metals, that crystallization occurred under vibratory action. Nevertheless, the report did lead the English Board of Trade to formulate some requirements regarding stresses in bridge construction. Stephen P. Timoshenko notes this in comments appended to R. E. Peterson's Discussions of a Century Ago concerning the Nature of Fatigue, and Review of Some of the Subsequent