They are practical people in Baltimore, and have not let their Institute " for the promotion of the mechanic arts" dwindle into a mutual admiration society, as some other cities have done. From the report, which we have just received, we find that in the past year, sixteen lectures have been delivered on interesting and useful subjects, a School of Design has been eminently successful, and a course of twenty lectures on chemistry have been delivered to attentive audiences; altogether, the Maryland Institute is really working for its country's good. The last Annual Exhibition was eminently successful, and the next (the eleventh) will commence on Tuesday, the 5th of October, 1858. Inventors wishing to have space allotted to them should apply early to the Actuary, John S. Selby, or to the Superintendent, Samuel Hindes, Esq.