6-7/8 21-5/8 22-3/8 1 7 22 22-3/4 2 7-1/8 22-3/8 23-1/8 3 7-1/4 22-3/4 23-1/2 3 7-3/8 23-1/8 23-7/8 2 7-1/2 23-1/2 24-1/4 1 All hats larger than these are called "extra sizes." The average size, then, of the crania of white races in the United States, is about 22-1/2 inches circumference, including the hair and scalp, for which about 1-1/2 inches should be deducted, leaving a mean horizontal periphery, for adult males, of 21 inches. The measurements of the purest Teutonic races in Germany and other countries, would give a larger mean; and I have reason to believe that the population of France, which is principally Celtic, would yield a smaller mean. I hope that others will extend these observations. Dr. Morton's measurements of aboriginal American races, give a mean of but 19-1/2 inches; and this statement is greatly strengthened by the fact that the Mexicans and other Indian races wear much smaller hats than our white races. (See _Types of Mankind_, p. 289 and 453.) Prof. Tiedemann, of Heidelberg, asserts that the head of the negro is as large as that of the white man, but this we have shown to be an error. (_Types of Mankind_, p. 453.) Tiedemann adopted the vulgar error of grouping together under the term _Caucasian_, all the Indo-Germanic, Shemitic, and Nilotic races; also all the black and dark races of Africa under the term _Negro_. Now I have shown that the Hindoo and Egyptian races possess about 12 cubic inches less of brain than the Teutonic; and the Hottentots about 8 inches less than the Negro proper. I affirm that no valid reason has ever been assigned why the Teuton and Hindoo, or Hottentot and Negro, should be classed together in their cranial measurements. I can discover no facts which can assign a greater age to one of these races than another; and unless Professor Tiedemann can overcome these difficulties, he has no right to assume identity for the various races he is pleased to group under each of his arbitrary divisions. Mummies from the catacombs, and portraits on the monuments, show that the heads of races on both sides of the Red Sea have remained unchanged 4000 years. As Dr. Morton tabulated his skulls on the same arbitrary basis, I abandon his arrangement and present his facts as they stand in nature, allowing the reader to compare and judge for himself. The following table gives the _internal capacity_ in cubic inches, and it will be seen that the measurements arrange themselves in a sliding scale of 17 cubic inches from the Teuton down to the Hottentot and Australian. _Internal Capacity of Brain in Cubic Inches._