=Inscriptions.=--By inscriptions one means all writings other than books. Inscriptions are for the most part cut in stone, but some are on plates of bronze. At Pompeii they have been found traced on the walls in colors or with charcoal. Some have the character of commemorative inscriptions just as these are now attached to our statues and edifices; thus in the monument of Ancyra the emperor Augustus publishes the story of his life. The greatest number of inscriptions are epitaphs graven on tombs. Certain others fill the function of our placards, containing, as they do, a law or a regulation that was to be made public. The science of inscriptions is called Epigraphy. =Languages.=--The languages also which ancient peoples spoke throw light on their history. Comparing the words of two different languages, we perceive that the two have a common origin--an evidence that the peoples who spoke them were descended from the same stock. The science of languages is called Linguistics. =Lacunæ.=--It is not to be supposed that books, monuments, inscriptions, and languages are sufficient to give complete knowledge of the history of antiquity. They present many details which we could well afford to lose, but often what we care most to know escapes us. Scholars continue to dig and to decipher; each year new discoveries of inscriptions and monuments are made; but there remain still many gaps in our knowledge and probably some of these will always exist. RACES AND PEOPLES =Anthropology.=--The men who people the earth do not possess exact resemblances, some differing from others in stature, the form of the limbs and the head, the features of the face, the color of the hair and eyes. Other differences are found in language, intelligence, and sentiments. These variations permit us to separate the inhabitants of the earth into several groups which we call races. A _race_ is the aggregate of those men who resemble one another and are distinguished from all others. The common traits of a race--its characteristics--constitute the type of the race. For example, the type of the negro race is marked by black skin, frizzly hair, white teeth, flat nose, projecting lips, and prominent jaw. That part of Anthropology which concerns itself with races and their sub-divisions is called Ethnology.[3] This science is yet in its early development on account of its complete novelty, and is very complex since types of men are very numerous and often very difficult to differentiate. =The Races.=--The principal races are: 1.--The White race, which inhabits Europe, the north of Africa, and western Asia. 2.--The Yellow race in eastern Asia to which belong the Chinese, the Mongols, Turks, and Hungarians, who invaded Europe as conquerors. They have yellow skin, small regular eyes, prominent cheek-bones, and thin beard. 3.--The Black race, in central Africa. These are the Negroes, of black skin, flat nose, woolly hair.