Ship’s Letter Telegram. 
Located at one end of the North Atlantic shipping routes, Ireland played a key role in the shipping industry due to the location.
One of the main radio stations serving the the maritime shipping industry was located at Valentia Island, Co. Kerry. This was the site of the original Marconi radio station at the terminus of the Atlantic cable, and would relay instructions from and to ship’s masters and their companies in England or the northern coast of Europe. Most were sent by telegram to Valentia, and then transmitted by radio or vice-versa; however, some routine messages were received from the Ship’s Radio and then mailed to reduce costs. Since this was a government-operated facility, they were sent by official mail. (Figure 1).
Prior to and after WWII, this was a busy operation, but with the improvements in radio made during the war, it was no longer necessary for the radio station to be at water’s edge in an isolated section of western Ireland. Radios in England or Amsterdam were able to provide just as good service and at a lower cost. These, in turn, were replaced by satellite links.
Today, the Marconi Radio Station, its local railway station (the western-most railway station in Europe) are all gone. All that remains is a plaque and the bird sanctuary, oh, and, yes, the cover in my collection.