During his adventures, the narrator's brother meets Mrs. Elphinstone (who is married to Dr. Elphinstone, who isn't around) and Miss Elphinstone (who is Dr. Elphinstone's sister). They are a good example of how two characters can be used to contrast each other. Let's take a look. Mrs. Elphinstone is short and dressed in white; Miss Elphinstone is tall and dark-colored. (You probably noticed this isn't a perfect reversal in terms of colors – Mrs. is dressed in white while Miss has a dark complexion (which probably means black hair) – but you can see how they seem like contrasts of each other.)
Even more notable, Mrs. Elphinstone spends her time being nervous and calling for her husband, while Miss Elphinstone is calm and brave. Instead of crying out for an absent husband (which is what Mrs. does), Miss E fights back when people attack them.
As much as we enjoy the Elphinstones, there's some question as to why they're in the book. Are they here just to give the brother someone to talk to or help? That doesn't entirely seem right. After all, if that were true, why would we need both of them? We're not sure about this, but it seems like the two Elphinstones are meant to show two different responses to the Martian invasion from women. And – surprise, surprise – different women react differently to a Martian invasion. Some women might react nervously while some of them might be brave. Now, this might be surprising to the Victorians who read this originally, but it turns out that women are people, too. (To be honest, we're somewhat influenced by Wells' later book Ann Veronica, which is all about the problems that women faced in late Victorian times. Whereas some other Victorians might not have cared about what women thought, Wells clearly did.)