 Within three hours the letters had been resealed and returned to the central post office to be delivered to their intended destination.As well as supplying the emperors of Austria with vital intelligence, the Viennese black chamber sold the information it harvested to other European powers.In 1774, for example, an arrangement was made with Abbot Georgel, the secretary in the French embassy, who had access to a biweekly package on information for 1,000 ducats.