I agree that the boy who boasted about what he would do if he were rich, and had that silly argument with Mrs. Bennet, sounds quite young. I was trying out different scenarios about the Lucas family in my head (all with six children only, two boys and four girls).

a) Lady Lucas had her children in a nice, orderly fashion, two years apart. Since Charlotte is 27, that would make the other five (that we know of) 25, 23, 21, 19 and 17. Although we are told that Maria Lucas "had been little used to company" (ch.29), I do get the impression that she is "out" in society. Where does that leave the sisters who entertained hopes of "coming out a year or two earlier" when Charlotte became engaged? I can't imagine parents keeping girls already over the age of 21 from making their debut, no matter how strained their finances, with the spectre of old-maidenhood hovering at 27. So, let's say that the two siblings after Charlotte are boys, followed by Maria who would be 21, then the two nameless girls, but then, where does that leave the arguing "young Lucas"?

b) Lady Lucas had her children more spread out, one every *three* years on average, which would make the youngest twelve, which sounds about right to me, but it seems unlikely in an era of (to say the least) unreliable birth control.

c) There were some longer gaps between at least some of the Lucas siblings, due to Lady Lucas' reproductive issues such as miscarriages, stillbirths or temporary infertility, other health problems, or children who died early in life. :-(

d) More happily, perhaps Lady Lucas had a surprise baby several years after she thought her child-bearing years were over. (I recently talked to a man whose grandmother discovered at age 50 that she was pregnant again, a good ten years after she thought her large family was complete, and had a healthy child.)

I don't think we can say for sure that "young Lucas" *was* a *third* boy (though I don't see why not! ;-), but I agree with you that he sounds like a boy in his mid-teens, at most.