At the beginning of Chapter 5 (Book I), Fielding points out that he often uses Slipslop as a foil to her mistress, Lady Booby. By making them both fall for Joseph, Fielding can point out the "different operations of this passion of love in the gentle and cultivated mind of Lady Booby, from those which it effected in the less-polished disposition of Mrs. Slipslop." Slipslop is a foil and also a coarse echo of Lady Booby; she is vain and proud and thus is "a mighty affecter of hard words" toward those whom she considers her inferiors, such as Mrs. Grave-airs and Fanny Goodwill. Yet there are also crucial differences between Slipslop and her mistress. Slipslop is ridiculous in a warm way; we laugh kindly at the incongruity of a fat, pimply, red-faced, lame, forty-five-year-old slob pursuing Joseph. But at least she is direct in her physical desires; when Adams mistakenly enters her bed, she realizes that he is not Joseph, but that he is better than nothing. Lady Booby could never do this. Slipslop may be a snob in some matters, but she is always superbly practical.