In reconstructing the sound system of old Chinese— the script being ideographic, the old pronunciation cannot simply be read off—we have been able, thanks to rich materials of various kinds, to determine with tolerable certainty, even in detail, the system of what we call Ancient Chinese, the language of the sixth century a.d., embodied in the dictionary Ts'ie yün. When the inquiry turns to older epochs, the materials are much more meagre and unsatisfactory, and at present, at least, it does not seem feasible to reconstruct in detail the language which we may call Archaic Chinese, the language of the Chou dynasty, the language of the classics. But we are not entirely at a loss. Important conclusions can be drawn regarding this stage of Chinese, and that by four different means. Perhaps the most important of all will be a comparative study of the sinitic family of languages; but for such researches time can hardly be said to be ripe as yet. The T'ai languages and the Tibeto-Burman languages will have to be thoroughly investigated and their most ancient forms established by comparative methods, before there is any use of comparing them with Chinese. But the three remaining sources are ready at hand even now, and some examples will be given here to show how they can be used for reaching new and interesting results about the sound system of Archaic Chinese.