Amongst the modern works to which I owe an obligation I may mention the two treatises _Mechanical, physical and chemical theories of the Ancient Hindus and the Positive Sciences of the Ancient Hindus_ by Dr B.N. Seal and my two works on Yoga _Study of Patanjali_ published by the Calcutta University, and _Yoga Philosophy in relation to other Indian Systems of Thought_ which is shortly to be published, and my _Natural Philosophy of the Ancient Hindus_, awaiting publication with the Calcutta University. Gu@naratna mentions two other authoritative Sâ@mkhya works, viz. _Mâ@tharabhâ@sya_ and _Âtreyatantra_. Of these the second is probably the same as Caraka's treatment of Sâ@mkhya, for we know that the sage Atri is the speaker in Caraka's work and for that it was called Âtreyasa@mhitâ or Âtreyatantra. Nothing is known of the Mâtharabhâsya [Footnote ref 1]. An Early School of Sâ@mkhya. It is important for the history of Sâ@mkhya philosophy that Caraka's treatment of it, which so far as I know has never been dealt with in any of the modern studies of Sâ@mkhya, should be brought before the notice of the students of this philosophy. According to Caraka there are six elements (_dhâtus_), viz. the five elements such as âkâs'a, vâyu etc. and cetanâ, called also puru@sa. From other points of view, the categories may be said to be twenty-four only, viz. the ten senses (five cognitive and five conative), manas, the five objects of senses and the eightfold prak@rti (prak@rti, mahat, aha@mkâra and the five elements)[Footnote ref 2]. The manas works through the senses. It is atomic and its existence is proved by the fact that in spite of the existence of the senses there cannot be any knowledge unless manas is in touch with them. There are two movements of manas as indeterminate sensing (_ûha_) and conceiving (_vicâra_) before definite understanding (_buddhi_) arises. Each of the five senses is the product of the combination of five elements but the auditory sense is made with a preponderance of akasa, the sense of touch with a preponderance _________________________________________________________________ [Footnote 1: Readers unacquainted with Sâ@mkhya-Yoga may omit the following three sections at the time of first reading.] [Footnote 2: Puru@a is here excluded from the list. Cakrapâ@ni, the commentator, says that the prak@rti and puru@sa both being unmanifested, the two together have been counted as one. _Prak@rtivyatiriktañcodâsîna@m puru@samavyaktatvasâdharmyât avyaktâyâm prak@rtâveva prak@sipya avyaktas'avbdenaiva g@rh@nâti._ Harinâtha Vis'ârada's edition of _Caraka, S'ârîra_, p. 4.] 214