Recently, while searching for a relative in the census, I came upon an interesting situation

The relative was boarding with a fellow worker.  The situation had to do with the fellow worker.

There was a head of the household, John.  He was married to Mary.  The “fellow worker” was Richard, and he was married to Jane.

John was listed as Head of the household, and his wife, Mary, was listed as wife.

Richard was listed as Brother-in-law, and Jane was listed as Sister-in-law.

Was Richard the brother of John’s wife, Mary, or was Richard the husband of Mary’s sister (Jane)?  Was Jane the sister of John’s wife, Mary, or was Jane the wife of Mary’s brother (Richard)?

Something to think about!