Will asks, "What does flatly mean?"
He's become intrigued with adverbs. Henry Huggins says things coldly, bravely, calmly, enviously, casually, reluctantly, frantically. Will doesn't want to miss a single nuance of Henry's expressive speech.
"Slowly" is an adverb I find hard to resist. It can be suggestive of effort as well as of ease, of suspense as well as of repose. When I ran a net search on the adverb "slowly," the search results included both pornography and technical support ("does your simulation run too slowly?"). Slowness is a positive attribute of sex ("... slowly oooohhhh ..."), but a disadvantage when running computer programs. We want to interact slowly with each other's bodies, but we expect our interaction with machines to proceed quickly. Is this why pornography has adapted so well to the Internet, because it takes advantage of simulations that run slowly?
My favorite use of the adverb "slowly," however, is in the directions for making Campbell's Tomato Soup: "Slowly stir together soup and one can of water OR, for a creamier soup, use one can of milk." The adverb is crucial. If you fail to add the water slowly, the soup is clotted and lumpy. Despite the modern convenience of a condensed soup in a can, a little old-fashioned slowness must be reclaimed in the preparation. The directions conclude: "promptly refrigerate any unused portion in separate container." In condensed form, Campbell's Tomato Soup offers both promptness and slowness, a balanced adverbial diet.
Will himself slurps his soup slowly, expressively. As he slurps his last spoonful, I ask him if he would like seconds.
"Nope," he says, soupily, before slowly moving on to something new.