Third letter to the Right Hon. H. Labouchere, M.P. &c. &c. on the balance of trade, ascertained from the market value of all articles imported, as compared with the market value of all articles exported, during the five years ending January 1850 [electronic resource] : further tested by reference to the balance of trade between the United Kingdom and her colonies, which has been similarly ascertained / by C.N. Newdegate