The Brahmanas are particularly noted for their instructions on the proper performance of rituals, as well as explanations on the symbolic importance of sacred words and ritual actions. Academics such as P. Alper, K. Klostermaier and F.M, Muller state that these instructions insist on exact pronunciation (accent), chhandas (छन्दः, meters), precise pitch, with coordinated movement of hand and fingers - that is, perfect delivery. Klostermaier adds that the Satapatha Brahamana, for example, states that verbal perfection made a mantra infallible, while one mistake made it powerless. Scholars suggest that this orthological perfection preserved Vedas in an age when writing technology was not in vogue, and the voluminous collection of Vedic knowledge were taught to and memorized by dedicated students through Svādhyāya, then remembered and verbally transmitted from one generation to the next. It seems breaking silence too early in at least one ritual is permissible in the Satapatha (1.1.4.9), where 'in that case mutter some Rik [RigVeda] or Yagus-text [YajurVeda] addressed to Vishnu; for Vishnu is the sacrifice, so that he thereby regains obtains a hold on the sacrifice, and penance is there by done by him'.