It is as difficult to separate the current of Scottish migration to the American Colonies, or to the United States that grew out of them, from the larger stream which issued from England, as it is to distinguish during the last two hundred years the contributions by Scotsmen from those of Englishmen to the great body of English literature. We have the first census of the new Republic, in the year 1790, and an investigator who classified this enumeration according to what he conceived to be the nationality of the names, found that the total free, white, population numbering 3,250,000 contained 2,345,844 people of English origin; 188,589 of Scottish origin, and 44,273 of Irish origin. The system of classification is manifestly loose, and the distribution of parent nationalities entirely at variance with known facts. That part of the population described as Irish was largely Ulster-Scottish, the true Irish never having emigrated in any considerable numbers until they felt the pressure of the potato famine, fifty years later. There is excellent authority for the statement that, at the outbreak of the Revolutionary War one-third of the entire population of Pennsylvania was of Ulster-Scottish origin. A New England historian, quoted by Whitelaw Reid, counts that between 1730 and 1770 at least half a million souls were transferred from Ulster to the Colonies--more than half of the Presbyterian population of Ulster--and that at the time of the Revolution they made one-sixth of the total population of the nascent Republic. Another authority fixes the inhabitants of Scottish ancestry in the nine Colonies south of New England at about 385,000. He counts that less than half of the entire population of the Colonies was of English origin, and that nearly, or quite one-third of it, had a direct Scottish ancestry.