E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Assay
or Essay. To take the assay is to taste wine to prove it is not poisoned. Hence, to try, to taste; a savour, trial, or sample. Holinshed says, Wolsey made dukes and earls serve him of wine with a say taken (p. 847).
1
Edmund, in King Lear (v. 5), says to Edgar, Thy tongue, some say of breeding breathes; i.e. thy speech gives indication of good breedingit savours of it. Hence the expression, I make my first assay (trial).