The top envelope was carried in the British airship R34 on her non-stop journey of 75 hours between New York and Pulham in Norfolk. The two envelopes in the middle of the picture mark the attempt, by Harry Hawker and Mackenzie Grieve in a Sopwith, to be the first to cros the Atlantic by air. Departing from Newfoundland they flew into adverse weather conditions. 1400 miles out they ditched near a Danish steamer so small that it carried no radio and they were given up for lost for 7 days. Their aeroplane did not sink, was salvaged by an American ship, and the few letters that remained in it were delivered by the British Post Office with an 'officially secured' label. The bottom envelope is from the first succesful non-stop Atlantic flight that took place in 1919.
© Science Museum / Science & Society Picture Library