Final answer:
The metaphor describes the ladies' efforts to remain elegant and composed, using a suggestive comparison to frosted teacakes, despite the sweltering heat that causes them to sweat.
Step-by-step explanation:
The phrase "like soft teacakes with frostings of sweat and sweet talcum" suggests that despite the heat, the ladies still attempted to maintain their composure and ladylike appearance. This metaphor compares the women's state after their daily routines - bathing and applying talcum powder - to teacakes that are soft and covered with frosting, evoking an image of delicate upkeep despite the sweltering heat which causes them to sweat. The mention of sweat and talcum points to a contrast between the uncomfortable climate and their efforts to stay fresh and presentable.