of the pier columns under load. An extreme instance of such compression is that in the Niagara Cantilever bridge.

Timber piers are merely a makeshift, so do not merit much consideration. They are employed sometimes to support steel bridges until money is available for building masonry piers. It is seldom that timber piers are built in large rivers where the current is rapid and the scour is great. The author was once forced by circumstances into building pile piers under these conditions; and although they are still standing, he would sleep better at certain seasons of the year, had they never been built. The piers referred to are the temporary piers of the East Omaha bridge over the Missouri River. They were constructed in the winter, mostly on the sand-bar, by driving groups of seventy-foot red-cypress piles fifty feet into the sand by means of a powerful water-jet, then sheathing the sides and nose with four-inch oak plunks and bracing the piles on the inside. The nose of each pier is on an incline, faced with steel plates where the ice can reach it, and forming a cutting edge that is capped with a heavy railroad rail. Each pier is surrounded with a woven willow mattress, eighteen inches thick, of the most substantial character, sunk and kept in place with rock. These piers have received a much more severe test than was anticipated when they were designed, because the channel has shifted across the river, so that at times there are thirty-five feet of water where there was a dry sandbar when the bridge was constructed. The mattresses have not been injured by the scour, but have simply been lowered, the edges going deeper than the portions near the piers. The only ill effect noticeable is the springing down-stream of the tops of two piers, in one case about six inches and in the other about eleven inches. In order to bring the tops of these piers partially back to place and prevent any further deflection, the author employed a detail which has proved to be very satisfactory. It consists in passing one end of a strong iron chain loosely around an up-stream pile and dropping the loop to the bottom, then attaching near the other end of the chain a steel rod with an adjustment. A number of these chains were used for each   pier,   the   rods   passing  through  heavy   timbers  at   the