But tlie less quantity of iron required to do tlio worlds not tho wliolo explanation of 
tlie less cost of American as compared with English bridges. A second and equally 
important reason is tlie less amount of manual labor required to construct and ereot 
tliem — owing to tlie general use of machinery in forming all tlie parts. 
English bridges are made of low-price iron and require a groat deal of it-, and a 
great deal of hand-labor in constructing and erecting. 
American bridges have all tlieir principal parts formed by machinery. They are 
of exact uniform dimensions, in similar spans, and lienee perfectly interchangeable, 
like tlie parts of tlio locks of tlie American rifles, or of sewing-machines. Hence 
machino-labor can be applied to thoir manufacture, and tho cost at tho works rc- 
(liiCGd to a minimum. 
But American bridges have still auotlier advantage. They arc so made that 
nearly all tlie work is clone at tho sliopg, and they can bo croctod with tlio least pos- 
8 ル 1 〇 amount of labor, and that unskilled. In fact, tlie cost of erecting tlio staging 
tho principal expense ; after that a 200 foot span can be orcctod and made self-sus- 
taining in tlio space of two days, if necessary. 
But the English bridge is only about half clone when the scaffolding is built and 
tlio iron placed upon it. It has then to be riveted together, which is expensive, as 
tlie conveniences for such work at the site of a bridge are not often groat. It is slow 
anti tedious, requiring from two to three weeks to put together a 200 feet span. 
Taking all these tilings into account, ifc will bo seon liow American bridge-build- 
ei’s liave been able to compete with English firms on the large bridge at Buffalo, 
and iu tlio recent case of tlie long span bridges of tlio Intercolonial Eailroad of 
Canada. M 
I have dwelt at length upon tlio comparison of American and European bridges, 
for the reason that the Japanese railroad bridges are of the latter type. 
It will now be necessary for me to criticize tlie railroad bridges of this country, 
and I hope you will excuse me for so doing. I have little hesitation in expressing 
m y opinion tbereou, knowing that tlie designs are not yours, but arc the work of 
some of the present and former foreign employees of the Eailway Department. 
llie first grave error to which I would call your attention is that both for 
economical and prudential reasons the spans are too short, tlie superior limit being 
0116 hundred feet. For any locality that bridge is tlio most economical, for which 
tlie total cost of both superstructure and foundations is a minimum, provided that 
tli デ waterway be not so lessened as to endanger tlie structure from washout or to 
raise t]ie flood level of tlio river enough to injur o the surrounding country. 
Now as the cost of foundations is always very uncertain and in most cases exce- 
ocls tho estimate, ifc is clear that long spans, especially over tho deepest part of tho 
llver, ave liable to be more economical than short ones, and no one will deny that 
a 8 P an of one liumlred feet is a short one. Agaiu, for such spans tbo contraction of 
waterway is least ten per cent, which, in addition to tlie piling np of the water by 
10 iru pn；ct of tlio current against the piers, ■will cause a decided increase in the 
flood level. 
If an American engineer were sent to inspect and pass judgment upon a 
