Those who had the widest experience of the Peninsula were convinced that its races were at least as varied as those of Europe: those who, like Mr Nesfield, had made a close study of one limited tract, might have continued to believe that under the superficial distinctions of caste and class lay a real unity of race. But Mr (afterwards Sir H. H.) Risley had spent the early years of his Indian service among the Dravidian tribes of Chota Nagpore, and was aware that they differ more widely from the people Mr Nesfield had studied than an Englishman differs from a Turk. The difference, indeed, was almost as great as that between a European and a Chinaman. Could such differences be registered and described in such a way as to convince minds accustomed to scientific accuracy in statement? Mr Risley thought he saw his way to an ethnological classification of Indian races and castes by means of the then comparatively new methods of anthropometry. In 1891, he published in the _Journal of the Anthropological Institute_ a paper which marked the beginning of systematic ethnological studies in India. It contained a summary of the measurements of eighty-nine castes and tribes of Bengal, the United Provinces, and Bihār. It dealt, therefore, with the great alluvial plain, created by the Ganges and Indus, which lies between the Himalayas and the _massif central_ of the Deccan. Here is the home of the Aryan immigrants, where the great Indo-European languages are spoken by communities as numerous as the larger European nations. Anthropometry showed in the plainest, the most incontrovertible way, that the caste system of marriages had sorted out men into classes possessing definite and recognisable physical characteristics. There were local differences, and caste differences. It only remained to extend anthropometrical measurements to other parts of India to prove that the many languages and religious beliefs of India are associated with an even greater variety of physical qualities. Such enquiries are still in progress, but many notable results have already been obtained, especially by Mr Edgar Thurston, in his now famous investigations into Dravidian ethnography.