network, a system was instituted to give shipping warning of approaching gales. It would give boats in Port Jackson warning of approaching busters. The new signals were included in Gowland's amendments to the NSW Sailing Directory The signal was a diamond shape (see Day shapes) on the southern yard-arm of the signal mast to indicate a squall approaching from the south, and numeral pendants per John Nicholson's Code of Signals flying on the masthead to show the location of the squall. The numbers were those already in use from 1842 for identifying ports, e.g. Jervis Bay was 46 and Wollongong, added in 1854, was 82. The signal masts were at South Head Signal Station and Fort Phillip. These masts had two yard-arms at right angles aligned north–south and east–west. The success of the system was seen in 1870 when a newspaper reported, "About 9 o'clock, however, intelligence of a southerly burster was telegraphed from Eden, and by half-past 12 the expected 'brickfielder' blew over the city." From 1876 signals would be displayed at two additional places - the new flagstaff at Bradley's Head and the Floating Light Vessel at the entrance to the Harbour. This direction specified that a cone signal on the flagstaff would indicate the approach of a southerly squall. This signal, "A cone, with the point downwards, shows that a gale is probable; at first from the southward.", was introduced in England 1861 by Robert Fitzroy, but this appears to be the first time it was used in Port Jackson. In 1879, George Herbert Gibson published a book called Southerly Busters, where a buster wreaks havoc near Hyde Park, Sydney. In November 1898, the Postmaster General, Varney Parkes, announced that a white flag with the letters E, J.B. or W would be flown from the flagstaff on the clock tower of the General Post Office, Sydney to signal the approach of a southerly buster. As the wind reached Eden, Jervis Bay or Wollongong the relevant flag would be hoisted. The J.B. flag was hoisted for the first time on 10 February 1899 but the wind did not travel beyond Kiama. The day had been hot and oppressive and the much anticipated cool change didn't eventuate. The original intention was to change the flags as the change moved north but this didn't always happen. It was possibly later reduced to just two flags, JB and W. 20th century