unperceivingly

And indeed Balzac's confident way is not one that would give a good result in most hands; it would produce the kind of description that the eye travels over unperceivingly, the conscientious introduction that tells us nothing.

The Craft of Fiction Percy Lubbock 1922

She had opened at one of the tables, unperceivingly, a big volume of which she turned the leaves.

The Awkward Age Henry James 1879