CONCRETE COLUMN DAM AT NIAGARA.
Two weeks ago there appeared in these columns an account of a novel dam building at Niagara. A concrete column fifty feet high and seven feet four inches square was built on a trestle in Victoria park, on the Canadian side of the falls. In order that the column should break evenly into sections, when it was tipped over into the stream where it was to form the dam, wooden wedges were inserted at every eight feet. These were twelve inches thick at the outside, tapering to six inches at the centre of the column, through which ran a chain to hold the sections together when the column broke. The trestle on which it was built was twenty feet high above the ground level. The process of tipping the column took ninety minutes. Under the timbers of the trestle three jacks operated, and for the first few inches of elevation of the timbers there was hardly any slant to be seen in the column. Soon, however, it began to lean towards the river, then very suddenly and very quickly it fell into the water underneath which its two ends disappeared, leaving the centre elevated, to settle down later. The accompanying illustrations, reproduced by the courtesy of the Scientific American, show two views, taken one after the other, of tipping the column into the stream and another of the column in the stream, broken as was designed, into fragments. The object of building the trestle, it may be added, was that it should fall, with the column. so as to cause its inner end to he thrown some fifteen feet out from the shore, and in that way leave an ice-mn between the shore and the end of the column. This has been accomplished. Since the fall of the column the water in the intake has been increased ten inches and one-half, which will afford a full supply to the pumping station of the Niagara Falls. Out,, pumping station, and the Niagara Falls Park & River railway for power purposes—the intake being used joint ly for both purposes.
In preparation for possible winter fires, the citizens of Traverse City, Mich., are having their private chemical extinguishers examined and recharged.