Mr. Maillefert, of this city, has invented an improved diving bell which he calls an Eeros-tatic tubular one; it is composed of an ordinary bell having in addition an outer case which can be filled with air to raise it, and a long tube from the bell, having ladders inside and shutters so arranged that the workmen can ascend and descend without the necessity of bringing up the bell each time, as the tube projects above the surface of tne water. An experiment was tried with it at Hunter's Point, L. I., in eighteen feet depth. As soon as the bell had been lowered, the men descended by the tube and remained in it five hours; they then ascended for dinner, and afterwards went down again and remained another five hours, working all the time on the submarine railroad track. They could hear distinctly all that was said on shore 150 feet distant, and were much satisfied with the experiment. Sufficient light passes down the tube to enable them to see how to work.