Beautiful pneumatic post postcard

I came across this image on Pierre-Stéphane Proust's site, ArtPostal.com. He collects letters and cards of all sorts. The card at left belongs to a series of postcards published in the early 20th century (I would guess 1908 at the very latest, given the Art Nouveau stylings and dynamic lines). I love how it ties together the interfaces of the Poste Pneumatique, from licking a letter shut at a writing desk, to the lines that call to mind the pipes under the street, to the steam-powered receiving apparatus in the corner, to the Carte Pneumatique on the other end. Who's the addressee? The person holding the card, of course. This card belongs to a wonderful series of post through the ages, from the pyramids to the telegraphs.