These studies attempt to answer a number of basic questions concerning the nature of the business activity of the Anglo- Jewish 'patriciate' and the economic foundations on which it stood. It is impossible to measure the Jews' role in statistical terms. Only in regard to the Anglo-Indian diamond trade do we have sufficient numerical data to enable us to draw accurate conclusions about the Jews' part in that branch of commerce. For all other fields of business activity we must be content with evidence of a different kind, but although the latter will never have the same degree of accuracy inherent in comprehensive and reliable statistical information, it may still carry much weight.
The most striking aspect of Jewish business activity is the degree of its specialization. At first sight this specialization may seem to bear a geographical character — Jews traded mainly to the Iberian peninsula and its colonies, to India, Holland and Leghorn. But a close examination will show that Jews, on the whole, tended to concentrate in certain branches which determined the geographical limits of their activities, and not vice- versa. They were most prominent in the precious metals, diamonds and exchange trades - all very much in accord with Jewish commercial tradition, though they also played a significant part in other fields: in the supply of manufactured goods to the Spanish colonies in America, in the trade in the agricultural products of the Spanish and Portuguese colonies - mainly dye-stuffs, but also coffee, sugar etc. - and in the distribution of Indian goods in Europe.
A distinction must be made between Jewish activities in the Latin-American and in the Indian trades. The difference concerns not only the sort of goods dealt in, but also the merchants themselves : the Jewish businessmen who invested in Latin-American trade mostly belonged to the Portuguese community, while Indian goods were distributed mainly by Ashkenazim, resident in England, Holland and Germany.
The specialization in 'Jewish' branches of trade was less marked in the case of Portuguese Jews. It can, of course, be maintained that the export of consumer goods to Latin America