The short a is the substitute of i of the ātmanepada first person singular in the Potential and Benedictive.,
Thus पचेय, यजेय, कृषीय, हृषीय ।
Q.-- In the sutra, the word अत् is used, and the final त् belongs to the विभक्ति, therefore by rule (1. 3. 4), this त् is not indicatory; why is it made so ?
A.-- This त is not any portion or member of the substitute; it is added to अ merely for the sake of euphony.
The इट् refers to the आत्मनेपद affix of the first person singular; and not to the augment इट् on the strength of the maxim अर्थवद्ग्रहणे नानर्थकस्य । A combination of letters capable of expressing a meaning denotes, whenever it is employed in grammar, that combination of letters in so far as it possesses that meaning, but it does not denote the same combination of letters void of a meaning.,