A proposal has recently been made to construct a tunnel under the Humber from Barton to Hessle, close to Hull. A bridge over the river has often been spoken of; but its estimated cost, £700,000, render its construction hopeless. It is considered that the tunnel, which would be about 2,000 yards long, could be constructed for £150 a yard, and, with an allowance of £50,000 for approaches, the total cost would not exceed £350,000. It is not probable, however, that the railway companies concentrating on both sides of the river would find it to their interests, at all events at present, to carry this project into execution. The company that would most benefit by it would be the Manchester, Sheffield and Lincolnshire. Mr. Peter W. Barlow, civil engineer, has recently obtained permission from the City Commissioners of Sewers to construct a subway beneath the Thames, which is to be carried from Lower Thames Street to the opposite shore of the river. The dimensions of the subway are to be sufficient to allow a loaded omnibus to pass through it. If constructed economically, there is no reason why it should not answer commercially. We perceive by recent accounts from America that it was originally intended to connect the railways concentrating on both banks of the Mississippi at St. Louis, by a tunnel under the bed of the river; but this plan has been abandoned, and instead of it a “sub-aqueous iron tubular bridge” is to be laid on the bed of the river, which is about half a mile wide in this vicinity.