The Sixth Annual Exhibition of this Institute will be opened in the City ol Baltimore, on the 3rd ot October next. Articles intended for the Exhibition will be received on Monday the 26th of September, and those designed for exhibition only will he received during that week, but those deposited for competition and premium must be entered before Thursday night, Sept. 29. Particular information in regard to the arrangements and management of the Institute may be obtained by addressing John S. Selby, Actuary of the M. M. I., Baltimore, Md. Our readers are well aware of the high character that this Ins'itute sustains, and we have no doubt tbat this display will equal if not surpass that of any iormer yearit will be one ot unusual interest and utility. The ofh" cers and managers are men well qualified to give satisfaction to exhibitors, and they will use every precaution to give confidence and insure harmony and good feeling. Tbe Hall in which the Fair will be held, our readers will remember, was described on page 32, Vol. 7, Scientific American ; it is a spacious and beautiful edifice, and will probably accommo-dite all who may wish to offer the products of their skill, ingenuity and taste for public observation. The Exhibition will close on or before Oct. 31. A convention of some of our Southwestern States, just assembled at Memphis Tenn., has declared by resolution, that Cuba should be ours of a necessity. Rock: salt is said to have been found in the neighboihood of Rome, Ga.