Bert van Dijk Wire for organ actions since the 19th century
Het ORGEL 100 (2004), nr. 6, 22-24 [summary]

In the second half of the 19th century, brass wire appeared to be insufficiently reliable to organ builders. They suspected the ‘light gas’ that fuelled the lamps in the churches. In the meantime however, a much more important pollution factor has been discovered: the smelly gases from the canals made the zinc in brass (which consists of 20% zinc and 80% copper) dissolve, so that the brass became brittle.
Not only Dutch organ builders, like Witte, were confronted with this problem; Cavaillé-Coll was, too. In 1881, he decided to replace the brass wire in his organ at the Amsterdam Paleis voor Volksvlijt (1875, now at Haarlem) with ‘neosilver’ (30% nickel, 47% copper, 23% zinc). Other organ builders (Van Gelder, Van der Kleij) experimented with bronze and aluminium.