[1] His principal work is the Lehrbuch der politischen Ökonomie (1826–37), an encyclopaedia of the economic knowledge of his time, written with a special view to the guidance of practical men.
The two last he recognizes as admitting of variations in accordance with the special circumstances of different countries, while the first is more akin to the exact sciences, and is in many respects capable of being treated, or at least illustrated, mathematically.
It is a consequence in part of his conformity to their method and his attention to administrative applications that his treatise was found peculiarly adapted for the use of the official class and long maintained its position as their special textbook.
To the end, he occupied a somewhat indeterminate position with respect to that school; he subordinated historical investigation to immediate practical interests, and politics moved in the direction of limiting rather than extending the sphere of state action.
His general merits are thoroughness of treatment, accuracy of statement, and balance of judgment; he shows much industry in the collection and skill in the utilization of statistical facts; and his exposition is orderly and clear.