It was decided by our State Courts that ' The Art Union " of New York was a lottery. The American Institute at its present Fair, has flung the gauntlet of contempt at such a legal imputation upon such an Institution as an " Art Union." At the East end of the machine room there is suspended a picture resembling the scene of '' The Money Changers " in the Temple at Jerusalem. Connected with it is the flaming sign, " Art Union," for the relief of Broadway, by steam carriages. At the desk beneath, a subscription list has been opened, and subscribers solicited. The object of this Art Union is the formation of a company for the relief ot Broadway, by the substitution of steam carriages in place of horse omnibuses. We shall say nothing about the impracticability of such notions being carried out; but we do say, that no company has received, nor can receive, the privilege ot running steam.carriages in Broadway, and to form a joint-stock company for this purpose is a most extraordinary proceeding. And how does the conduct of the American Institute comport with true ideas of right and honor? It certainly appeared as an abettor of this scheme, or why did the managers allow part of the Fair to be turned into a subscription box? The Fair, in this respect, is an infliction upon visitors and a disgrace to our city : it has become a vender of spurious titles ; for it is not an exhibition of American Industry only, but a dealer in baseless projects. Any person or persons have a perfect right to form all kinds of legal joint-stock companies for testing any scheme, practicable or impracticable, but the Fair of the Institute is not the place for selling stocks for such projects