Mr. T.R. Cramton, who at the Southampton meeting of the British Association suggested a method of tunneling which, under certain conditions, seems of excellent promise, brought forward a suggestion at Southport for the construction of three-way tunnels. Now, the undoubted aim of all engineers is economy of construction and the securing of permanent advantages. Mr. Crampton maintains that the suggested system will give these, that three tunnels of, say, 17 ft. diameter, can be constructed cheaper than one of 30 ft. diameter. After describing Sir J. C. Hawkshaw's scheme for the ventilation of long tunnels, the three-way scheme was discussed. Three separate tunnels of 17 ft. diameter each, or 227 ft. area, are to be connected by large passages about midway of their length. These passages are without valves; in fact, free air passages. Between these midway connections and the ends, say again midway between, is formed a branch at right angles either above or below with separate openings from the branch into the other tunnels, such openings being provided with doors or valves quite clear of the main tunnel, any two of which may be closed, thus separating at this point the corresponding tunnels from the third.

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