A German physicist's travels in Great Britain Julius Plücker's visits from 1853 to 1866.

Today, we take international collaborations as a necessity, but 150 years ago, when travel was not so convenient, it involved an enduring and time-consuming challenge. This paper presents letters and reports written by German physicist Julius Plücker to his wife, Antonie née Altstädten describing his travels to Great Britain and France between 1853 and 1866. These letters provide a view into how international collaboration and communication were developed and maintained as well as how friendships were built within the scientific community during the early industrial age, prior to telegraph, telephone, email, and internet.