Lusitania in New York.
The picture is from the digitalized Bain collection on the site of the US library of Congress. They say it is in the public domain and are free to publish. Higher resolution examples can be downloaded there.
Hi Martin. Just had a look at the three mail chute photos. As pictures I didn't find them that interesting. You may perhaps care to post them? There's a picture of an airplane somewhere in the same place with the information that this one flies ahead with mail from some passenger ship that launches it. Not much of a photo either, but the act of launching could be. Regards, Stein.