Please answer a question about the following article about Alexander Graham Bell:

The Bell family home was in Cambridge, Massachusetts, until 1880 when Bell's father-in-law bought a house in Washington, D.C., and later in 1882 bought a home in the same city for Bell's family, so that they could be with him while he attended to the numerous court cases involving patent disputes.

In what year did Bell acquire a house in D.C.?
1882