When transformation of parts of speech takes place, we should distinguish synchronism from diachronism, grammar from rhetoric anti fixity from temporariness.
He was looking up at the dusty windows with a sort of ecstatic fixity of expression, like a hunky immigrant catching his first sight of the Statue of Liberty.
With the glance the calm fixity of her features sublimed itself to an expression of refinement and warmth; it was like garish noon rising to the dignity of sunset in a couple of seconds.