A notable difference of opinion exists among economic historians as to the effect of harvest fluctuations on general economic conditions. The question has arisen, specifically, in the interpretation of European experience in the eighteenth century. T. S. Ashton has suggested that good harvests, both by cheapening food and thus setting free purchasing power for others forms of expenditure, and by providing ampler supplies of agricultural products used as industrial raw materials, had a stimulating effect on the economy. J. D. Chambers and G. E. Mingay have taken the opposite view. According to them, bad harvests may have had the more beneficial effect, for the incomes of landowners and farmers were higher in lean years, and their prosperity or distress was of greater consequence than the dearth or cheapness of provisions.

The literature of American economic history is replete with discussions of the crucial role of the ferrous industries in nineteenth-century economic development. Analysis of the internal wage structure in the industry, however, has been somewhat neglected in the historical treatment.

The turning point in the history of the Genoese merchants in Spain was the discovery of America and the subsequent opening of trading relations with the new continent. From then on, their ascent to economic predominance in Spain paralleled that nation's emergence as the dominant power of the sixteenth-century world. Fortune gave Spain two empires simultaneously, one in the Old World, the other in the New. Spain's unpreparedness for imperial responsibilities, particularly in the economic sphere, was the springboard for Genoese advancement. Strengthening and enlarging their colony in Seville —after 1503 the “door and port of the Indies” —the Genoese prepared to move across the Atlantic in the wake of Columbus.