3. For the sirovrata concerns the mode of the study of the Veda...

3. For (the sirovrata) concerns the mode of the study of the Veda; also on account of (that rite) being a heading in the samâkâra; and the restriction is like that of the libations.

What the text says as to a restriction connected with the 'vow of the head,' does not intimate a difference of vidyâs. For that vow does not form part of the vidyâ. The restriction refers only to a peculiarity of the study of the Veda on the part of the Âtharvanikas, being meant to establish that they should possess that special qualification which the rite produces; but it does not affect the vidyâ itself. This is proved by the subsequent clause, 'a man who has not performed that rite may not read the text,' which directly connects the rite with the studying of the text. And it is further proved by the fact that in the book of the Âtharvanikas, called 'sâmâkara, 'that rite is referred to as a rite connected with the Veda (not with the special vidyâ set forth in the Mundaka), viz. in the passage, 'this is explained already by the Veda-observance' (which extends the details of the sirovrata, there called veda-vrata, to other observances). By the knowledge of Brahman (referred to in the Mundaka-text 'let a man tell this science of Brahman to those only,' &c.), we have therefore to understand knowledge of the Veda in general. And that restriction is 'like that of the libations'--i.e. it is analogous to the restriction under which the sava-libations, beginning with the Saptasûrya-libation, and terminating with the Sataudana-libation, are offered in the one fire which is used by the followers of the Atharvan, and not in the ordinary three fires.