The Fresnel apparatus selected for the light-house on Sand Key, Fla., will be a brilliant flash light of the first magnitude, and may be expected to be lighted by the let of June. The Metropolitan Mechanics Fair, now in progress in the east wing of the Patent Office, has drawn together thousands of persons from the cities and surrounding country. A line of steamers is to be established between New Bedford and New York. The large blast pipe at the Crane Iron Works, Catasuqua, Lehigh, Pa., burst on the 24th ult. The works were damaged to an extent ot 840,000. Two furnaces turning out forty tons per day, were stopped. It will tike three months to repair the damages.— No one was hurt. The bill for the reduction of the value of our silver coin has been approved by the President, and goes into operation on the 1st ot June next. Experiments have been lately made at Chicago to ascertain the amount of oxygen necessary to support life. Six hundred persons having been placed in a hall in one ofthe hotels of that city all the doors and windows were closed, at the end of the third half hour it was found unsafe to continue the expeii-ment any longer. A doctor of Tarbes has left 35,000 francs reward for the discovery of the disease which kills off one-third of the yearly produce of leeches.