conceal a truss from view, judge very correctly of the elastic limit of the iron rods which they have never seen, and of which they do not even know the existence. For ample proof of the utter inefficiency of the present system, we have only to compare the reports of the railroad commissioners in almost any State, with the actual condition of the structures described. In one State a late annual report covers a whole railroad with the remark, "All of the bridges on this line are in excellent order;" and yet there were at that very time, and are now, on that road, several large wooden bridges with a factor of safety referred to the breaking-weight of not over _two_ under a fair load, assuming the iron rods to be of the very best material,--a point upon which there is no evidence whatever. There is, in fact, no difference which any ordinary inspection would detect between these bridges as they stand to-day, and the Tariffville bridge as it stood the day before it fell. In another State, an iron bridge is in use under heavy trains, which has a factor of only 2-1/2 instead of 6, and yet the State report pronounces it an excellent structure and a credit to the railroad company, which recklessly allows its trains to pass over it. In yet another State, the commissioners in 1874 reported that a certain bridge should be removed; and this was quite correct, as it was an eminently unsafe bridge. In 1875 they suggested the same thing again. In 1876 they say, "This bridge must be rebuilt the coming spring." In 1877 they again reported, "This bridge must be rebuilt before the spring opens. It is old, and will not be safe for the passage of trains over it, if the ice or freshet should take away the temporary trestles, which now in a great measure support the truss." A year later than that, in 1878, a public protest was made against the further use of that bridge, as the lower chords were rotten, broken, pulled apart, and the only thing that held it up was a trestle, liable at any time to be knocked out by the ice; and yet, after all this, in reply to the protest, the commissioners replied that they had just "tested" the bridge by running an engine over it, and pronounced it "safe for the present," whatever that may mean. Now, just how it was that this bridge, which was old, rotten, and worn out, which the commissioners themselves had condemned for four successive years, which they had said two years before must be rebuilt the coming spring, and which relied entirely upon a trestle liable at any time to be carried away, had suddenly become "safe for the present," is not plain to see.