Description: Siphon recorder tape.

Caption: The ink was sprayed onto the paper tape as an aerosol in a fine line. The code that was used on undersea cables until 1871 was invented by the German mathematician and physicist Professor Karl August Steinheil (1801-1870) in 1835. It took a great deal of skill to read and was quickly replaced by using a siphon recorder that operated on the Morse system.

Introduction: This recording of 1870 is from the Indo-European cable which linked Bombay to London. there are annotations in Kelvin's own hand. The siphon recorder was the first bubble jet printer and the instrument which recorded these signals was a prototype. the siphon recorder was used principally for receiving and recording telegraph messages via long distance and submarine telegraph cables.

Background: Even with the use of a sensitive cable galvanometer, the retardation (slowing down) of a telegraph signal over long distances meant that only six or seven words per minute could be transmitted. Kelvin determined to improve such matters and in 1867 he invented the siphon recorder which was based on Sturgeon's moving coil galvanometer. This invention almost trebled the rate of traffic on the system.

Historical Context: Manufacture - When: circa 1870 - Where: Unknown

Historical Context: Owned by Lord Kelvin - When: 1870-1899 - Where: University of Glasgow, Glasgow, Scotland

Historical Context: Owner - Who: Thomson, William, Professor (1824-1907) Sir William Thomson from 1866 and Ist Baron Kelvin of Largs from 1892 better known as Lord Kelvin

Historical Context: Part of samples taken from various telegraph relay stations - Where: Indo-European cable between Bombay and London

Historical Context: Part of samples taken from various telegraph relay stations on the Indo-European cable between Bombay and London - When: 1870 - Who: Thomson, William, Professor (1824-1907) Sir William Thomson from 1866 and Ist Baron Kelvin of Largs from 1892 better known as Lord Kelvin

Historical Context: Event - "Lord Kelvin: A life in science" exhibition, Hunterian Museum, University of Glasgow. Object on display in this exhibition.