the Atreya recension of the Black Yajur-Veda, one for the recension of the Charakas, and the third for the Madhyamdina recension of the White Yajur-Veda.
Of the Sama-Veda we have an ancient index in the Arsheya Brahmana, and others among the Parisishtas, or supplementary works; while one of the Atharva-Veda exists in manuscript in the British Museum.
It is appropriate to draw attention, furthermore, to a science which belongs to the Age of Philosophy. It is the science of geometry, which, like grammar, astronomy, and other sciences, owes its origin to India, and has its roots in religion, for geometry was developed in India from the rules for the construction of the altars. It should be remembered that the world owes its first lessons in geometry not to Greece, but to India, even if the Greeks of a later age cultivated the science with greater success than the Hindus. The system of decimal notation is also of Indian origin, as the Arabs first learned it from the Hindus and introduced it into Europe. All science must therefore recognize an obligation to India in this respect.
We have still to refer to the most important product of the Hindu mind in this Philosophic and Rationalistic Period. The inquiries started at the close of the Brahmanic and Epic Period in the Upanishads led to those deeper investigations and profound researches which are known as the six schools of Hindu Philosophy. The most abstruse problems of matter and
