Scarp is a small fairly rugged island approximately 4 miles square just north west of Harris. Although there is no population today, in the 19th century there were some 32 families living there, some 120 people. By 1934 this had dwindled to just under 100, without a telephone line to connect to the outside world, making Scarp an ideal location for Mr Zucker`s rocket trials, it being envisaged that not only mail, but essential supplies such as drugs could be conveyed.
Stamps of a more elaborate design had been prepared, depicting a speeding rocket and an island, but no denomination, this being determined by the colouration, green for printed matter and red for sealed letters and other items. These were to be franked with a similar postmark to that previously used but with the wording TRIAL FIRING / SCARP – HARRIS, and the date 28-VII-34. The tiny lettered part made reference to therocket mail fees, 2s6d printed matter and 5s sealed letter, certainly out of reach of most of the inhabitants.
A rocket was prepared and the launch apparatus asssembled on the beach of the eastern shore of Scarp, directed towards Harris. On Saturday 28th July the residents together with the Head Postmaster of Lochmaddy, Mr MacPherson, gathered to witness the dispatch of some 1200 items of mail including letters to KGV and the Prime Minister Ramsey Macdonald. Gerhard Zucker himself pressed the electric starting button, there was a dull explosion, a flash of flame and a cloud of thick smoke. When this cleared, the wrecked rocket and launch apparatus could be seen, surrounded by scattered and torn smouldering letters, which the islands inhabitants proceeded to extinguish and salvage. Mr Zucker stated that the disaster was the result of a fuel fault (apparently British fuel differed from German fuel) and the wrong cartridge being attached to the rocket, and stated he was determined to repeat the experiment with these matters rectified. In the interests of safety the second attempt was made from Castle Amhuinnsuidh on Harris itself, rather than across the Caolas on Scarp.
Of the original post, some 793 items had been saved and 142 fesh items were added, although these were still franked with the 28th July date. On Tuesday 31st July the launch was repeated. Again there was an explosion but at least part of the rocket took off, scattering mail like confetti. This was not a great success. The mail was reportedly all safely recovered and was forwarded to the local post office for the transmission by more conventional means.