Description: Colloidion balloon.

Caption: The resulting gossamer light material can carry a large static electric charge and would have looked quite spectacular with it's partner suspended from a chandelier as the original owner had done. With the balloons charged they would have dramatically swung away from each other.

Introduction: The collodion or collodium is a thin membrane of nitrocellulose or gun cotton so thin that it shows interference patterns like the colours seen on soap bubbles and thin films of oil on water. The material was prepared by evaporation of a solution of nitrocellulose in a 1:7 alcohol: ether mixture.

Background: It was sent to Lord Kelvin by its maker for assessment as a component in an electrometer. Sadly, it is obviously too large to be practical and there were better and more readily available materials. One of the less desirable properties of nitrocellulose is that it is also known as gun cotton, which is explosive. Lord Kelvin must have been sent many more of these nutty ideas but no others seem to survive. Perhaps he kept this one because it appealed to his sense of humour.

Historical Context: Discovery of nitrocellulose or gun cotton - Who: Sch?nbein, Christian Friedrich (1799-1868) German-Swiss chemist

Historical Context: Discovery of nitrocellulose or gun cotton by Sch?nbein - When: 1845 - Where: Basle, Switzerland

Historical Context: Manufacture - When: 1885 - Where: Glenlea, West Dulwhich, London S. E., England - Who: Hovenden, Fred

Historical Context: Sent to Lord Kelvin - When: November 20, 1885 - Where: Glasgow University, University Avenue, Glasgow, Scotland - Who: Thomson, William, Professor (1824-1907) Sir William Thomson from 1866 and Ist Baron Kelvin of Largs from 1892 better known as Lord Kelvin