Expatiate

[H]e expatiated on the inconveniences of trade, that carried from us the commodities of our country, and made a parcel of upſtarts as rich as men of the moſt ancient families of England.

Source: wiktionary

To the pure mind of Isabella thought of no other had arisen; and it was far better that the generous romance of her young heart should expatiate on the rival in heaven, than for a moment dread a rival on earth, and therefore become subject to jealousy...

Source: wiktionary

Governor Bellingham, in a loose gown and easy cap,—such as elderly gentlemen loved to indue themselves with, in their domestic privacy,—walked foremost, and appeared to be showing off his estate, and expatiating on his projected improvements.

Source: wiktionary

Now, as the business of standing mast-heads, ashore or afloat, is a very ancient and interesting one, let us in some measure expatiate here.

Source: wiktionary