For he had been as instructive as Milton’s "affable archangel;" and with something of the archangelic manner he told her how he had undertaken to show (what indeed had been attempted before, but not with that thoroughness, justice of comparison, and effectiveness of arrangement at which Mr. Casaubon aimed) that all the mythical systems or erratic mythical fragments in the world were corruptions of a tradition originally revealed.
There are no more uses of "erratic" in the book.
Show samples from other sources
Bus service was erratic and seemed to go nowhere, but the Federal Government had forced a highway or two through the swamps, thus giving the citizens an opportunity for free egress.
Harper Lee -- Go Set a Watchman
He’d given her an inappropriate, clumsy, but very direct compliment that she knew she would never forget and that had already set her heart to a new and erratic pounding.