Her readers.] Referring back to the Grandmother.
in an underhand way.] Under the disguise of a fairy story.
grandmother again.] That is, in the old conditions when people were not too exacting about accuracy.
luckless grandson.] A humorous way of referring to himself. The author had the misfortune to be born in the modern age of science.
Seven wings.] The word "wings" is here used, not for "wings" like those of birds, but for the sides of a large building, projecting out at an angle from the main building.
But what is the use....] The author here breaks off the story, as though it were useless to go on any further in these modern days when every thing has to be scientifically proved.
Some "what then?"] Some future existence about which explanations might be asked.
no grandmother of a grandmother.] No one, however old.
never admits defeat.] Refuses to believe in death.
teacherless evening.] Evening on which the teacher did not come.