Slide Rules

Cylindrical slide-rule made by Keuffel & Esser about in 1885, on patent by Edwin Thatcher in 1881

Loose pebbles were the first objects used to aid humans in calculating numbers. Later they were used as counters on ruled boards before a range of materials were used to suspend counters on wire frames. This fixed wire structure known as the 'abacus' was developed in India and later adopted in China and Europe.

Sydney Observatory and the Carte Du Ciel or Mapping the Stars Project

In Autumn 1886, George Gabriel Stokes, President of the Royal Society of London received a letter from Admiral Mouchez, the Director of the Paris Observatory, "… in response to the presentation of specimens of the admirable star photographs by the MM. Henry, several astronomers to whom they had been sent suggested that it would be well that a conference of astronomers of various nations should be held, with a view to taking concerted action for obtaining on a uniform plan a complete map of the whole starry heavens."

The 1879 Sydney International Exhibition

Interior of the Garden Palace, New South Wales Court, Sydney, 1879, Powerhouse Museum Collection

The Sydney International Exhibition opened the doors of its main building the 'Garden Palace' on 17 September 1879 and closed them seven months later. Many figures in colonial Sydney talked of the success of the huge project and the Commissioners of the Sydney International Exhibition certainly felt it had "undoubtedly emphasized a new era in the history of the Colony, and projected the value of Australia on the minds of the inhabitants of those older countries". But the 1,045,898 visitors that passed through its gates were perhaps the most eloquent testimony to its triumph.