The fax machine is older than the telephone
The fax machine feels like office equipment from the 1980s. The idea is from the 1840s, and the first working fax service opened before anyone had made a telephone call.
On 27 May 1843, Alexander Bain, a Scottish clockmaker, dated a patent for improvements in timepieces, electric printing and signal telegraphs. In his design a clock kept two pendulums in step, one at each end of a line. At the sending end, a probe swept across metal pins set in an insulating cylinder and sent a pulse whenever it touched metal. At the receiving end, a matching probe passed over chemically treated paper, which marked wherever the current arrived. Line by line, the pattern was rebuilt.
That is still the basic idea of a fax: break an image into lines, send each point as on or off, and keep both ends in step. Keeping them in step was the hard part. Bain's sender and receiver were never truly synchronised, and his machine was never used commercially.
A service between Paris and Lyon
The Italian physicist Giovanni Caselli made it work. He built his pantelegraph in Paris with the engineer Paul-Gustave Froment, and in 1860 Napoleon III visited the workshop and secured him access to the telegraph lines. The sender wrote with insulating ink on a metal plate. A heavy pendulum regulated both ends, and the receiving paper, soaked in potassium ferricyanide, darkened wherever current passed. A small sheet of about 25 words took 108 seconds.
Commercial service opened on the Paris–Lyon line in 1865 and was extended to Marseille in 1867. Its most common use was in banking, to check signatures: something a Morse telegram could never carry.
By the time Alexander Graham Bell said "Mr. Watson, come here" in Boston in March 1876, pictures had been travelling by wire in France for more than a decade.
The order makes sense once you see it. A telegraph line already carried on and off, and a picture can be cut into a great many ons and offs. A voice is a smoothly changing wave, and carrying it took a different kind of invention.
What was Caselli's pantelegraph most commonly used for?
Sending pictures by wire came before sending voices: the fax began in the 1840s, more than thirty years before the telephone.
