With the character of Mrs. Glegg, Eliot is satirizing middle-class women who take themselves too seriously and view themselves (wrongly) as members of the elite upper classes. While Eliot is sympathetic toward all of her characters, there are a few like Mrs. Glegg who exist in part for comedic effect. The humor in Eliot’s portrayal of Mrs. Glegg comes through in passages like the following:
Mrs Glegg chose to wear her bonnet in the house to-day — untied and tilted slightly, of course — a frequent practice of hers when she was on a visit, and happened to be in a severe humour: she didn’t know what draughts there might be in strange houses […] One would need to be learned in the fashions of those times to know how far in the rear of them Mrs Glegg’s slate-coloured silk-gown must have been; but from certain constellations of small yellow spots upon it, and a mouldy odour about it suggestive of a damp clothes-chest, it was probable that it belonged to a stratum of garments just old enough to have come recently into wear.
The quote effectively shows off Eliot’s ironic tone when it comes to Mrs. Glegg—the subtle “of course” about how Mrs. Glegg wears her bonnet hints at how seriously Mrs. Glegg takes herself and the description of Mrs. Glegg’s dress as “far in the rear” of what is actually fashionable communicates how, despite her self-importance, she is not actually convincing anyone of her superior social status. Mrs. Glegg’s arrogance combined with her messy clothes—that contain “small yellow spots” and a “mouldy odour”—demonstrate her ignorance about her true place in the class hierarchy.
With the character of Mr. Stelling—Tom’s teacher and an Oxford-educated minister—Eliot is satirizing clergymen who have no integrity in relation to teaching yet receive high praise and high incomes anyway. The following passage—which contains verbal irony—communicates Eliot’s satirical intentions:
Any of those low callings in which men are obliged to do good work at a low price were forbidden to clergymen: was it their fault if their only resource was to turn out very poor work at a high price? Besides, how should Mr Stelling be expected to know that education was a delicate and difficult business? any more than an animal endowed with a power of boring a hole through a rock should be expected to have wide views of excavation.
Here Eliot makes it clear that Mr. Stelling is a stand-in for this type of clergyman generally (by speaking of clergy as a collective) and also mocks him for his lack of teaching abilities. She does not actually believe that Mr. Stelling should not be expected to understand education as “a delicate and difficult business,” but is using verbal irony. She goes farther still by comparing him to an animal whose sole purpose is “boring a hole through a rock” with no wider views of excavation. In other words, Mr. Stelling's sole purpose is to earn money by doing the bare minimum, and he has no wider views of what education could be.
It is notable that part of the reason Mr. Stelling is highly regarded despite his lack of skills is due to the ignorance non-clergy (like Mr. Tulliver) have about what types of training clergy actually receive. Unlike the narrator, Mr. Tulliver is not aware of Mr. Stelling’s extreme limitations.