Thus by 1834 the commercial union of modern Germany was virtually accomplished. The Zollverein united the principal German states,[571] Austria excepted, and under this _régime_ industry, assured of a large domestic market, increased by leaps and bounds. But a new problem presented itself, namely, what system of taxation was to be adopted by the union as a whole. In 1834 the liberal Prussian tariff of 1818 was adopted without much opposition, but nothing more was attempted just then. Many of the manufacturers, however, especially the iron-smelters and the cotton and flax spinners, demanded a more substantial means of protection against foreign competition. This clamour became more intense as the need for iron and manufactured goods increased the demand for raw material. Hence from 1841—the date of the completed Zollverein—a new discussion arose between the partisans of the _status quo_, inclining towards free exchange, and the advocates of a more vigorous protection. List’s _National System_, advocating Protection, appeared at the psychological moment. This delightfully eloquent work is full of examples borrowed from history and experience. The peculiar condition of contemporary Germany was the one source of List’s inspiration, and since the work was written for the public at large it is remarkably free from all traces of the “schools.” Germany’s industry, the sole hope of her future greatness, had found scope for development only during the peace which followed 1815. It was still in its infancy, and found itself hard hit by the competition of England, with her long experience, her perfected machinery, and her gigantic output. This was the all-important fact for List. England, whose rivalry appeared so dangerous, had closed her markets to German agriculturists by her Corn Laws, while industrial competition was out of the question. Two other nations, France and the United States, destined, like Germany, to become great industrial Powers, indicated the path of emancipation. France, warned by the results of the Treaty of Eden (1786) as to the evils of English competition, hastened to defend her fortunes by means of prohibitive tariffs. Still more significant was the example of the United States, whose situation was in all respects comparable with that of Germany. In both cases economic independence was hardly yet fully established, the natural resources were abundant, the territory was vast, the population intelligent and industrious, with the hope of a great political future. Though scarcely free as yet, the Americans made the establishment of industry and the shutting out of English goods by means of protective tariffs their first care. Thus there was everywhere the same danger, the tyrannical supremacy of England, and the same method of defence, Protection. Would Germany alone stand aloof from adopting similar measures?