If we examine closely the figures just furnished by F. Perraud, and consider that the number of Catholics in Great Britain was only five hundred thousand in 1821, which, following his calculation, mounted to four million in 1864, if we look closely into the gradations of the increase marked in the various Censuses taken between those dates, we shall find that the Irish immigration has indeed played a most important part in the return of England toward Catholicity.
"Irish Race in the Past and the Present"
Aug. J. Thebaud
The Censuses taken in 1800 and 1810 had shown that the North was increasing two to one in population over the South, and the coming census, it was feared, would show a much larger increase in favor of the North; in fact, when the census for 1820 was published the division of the population was as follows: Free White.
"A History of the Republican Party"
George Washington Platt
Several partial Censuses indicate that in 1865-66 the Negro population lost as many by disease as the whites had lost in war.
"The Sequel of Appomattox A Chronicle of the Reunion of the States, Volume 32 In The Chronicles Of America Series"
Walter Lynwood Fleming