The regulation of duties of customs on imports and exports might perhaps be considered so intimately connected with the subject of trade and commerce as to require no separate mention in this place ; he would however allude to it because one of the chief benefits expected to flow from the Confederation was the free interchange of the products of the labor of each Province, without being subjected to any fiscal burden whatever ; and another was the assimilation of the tariffs. It was most important to see that no local legislature should by its separate action be able to put any such restrictions on the free interchange of commodities as to prevent the manufactures of the rest from finding a market in any one province, and thus from sharing in the advantages of the extended Union