Telegraph Siphon Recorder by Muirhead & Co.
Telegraph Siphon Recorder by Muirhead & Co. Ltd. from the Eastern Telegraph Company cable station in Aden. This was the receiving and transmitting cable station to Bombay. The Siphon Recorder was invented by Lord Kelvin in 1867 for use initially with the new trans-Atlantic telegraph cable laid successfully at the third attempt in 1865. Due to the length of the cable- 4,000 + miles – there was an immediate requirement for an instrument of unparalleled sensitivity and Lord Kelvin devised the Siphon Recorder to satisfy this need. As sensitive as the mirror galvanometer it had the advantage of also creating a permanent record of the received signal. The recorder translated the incoming signal into a series of squiggles on a paper ribbon and a revolving paper covered drum. These were then interpreted by a telegraph clerk. Siphon recorders were highly complex and expensive and were only used on long distances where the usual equipment was insufficient, in consequence they were never common and most surviving examples are in museums. The example on offer is probably dates from the 1880s. The instrument appears to be complete and in near immaculate in virtually “untouched museum condition”. The only defect I detect is the missing half of the glass pen which should extend to the right and dip down into the ink reservoir. I understand that the ink was drawn up along the glass pen rod by electrostatic action provided by the coils under the reservoir. It is signed by Muirhead & Co Ltd no less than four times on both sides and on top under the ink reservoir. This high precision instrument is an exceptionally rare example of a scarce and critically important piece of Victorian telegraphic technology made to the highest electrical and engineering standards of Victorian Britain. Size 13″ (33 cm) x 17” (43 cm) x 11″ (28 cm) high. For photo and further details of the Aden cable station go to http://www.atlantic-cable.com/CableCos/CandW/Eastern/