Images Dated 30th March 2004

Tide predicting machine: front view

Photograph of the front view of the tide-predicting machine, designed by Lord Kelvin in 1876. Constructed by Lege for the Indian government, it was used for 23 years as a means for automatically calculating the tides at Indian ports, as well as the Atlantic and Pacific coasts of Canada. The principle of the tide indicator is the geometric construction known as harmonic motion

© Illustrated London News Ltd/Mary Evans

Hjorths electro-magnetic motive engine

Sketch of the Danish inventor Hjorth's electro-magnetic motive engine. The motor was a significant development from earlier electro-magnetic engines, as it eliminated the electric spark that produced a destroying effect on conducting metals. This in turn broke the current, which had previously been a problem in engines of this type

© Illustrated London News Ltd/Mary Evans