Alexander Bain: Electrochemical telegraph


Fax machines. Who cares, right? Believe it or not, the fax machine is still alive and well and a viable device even in 2012. Perhaps even more interesting is that the fax machine dates back to 1843, when Edinburgh-based inventor Alexander Bain (who also patented the electric clock) demonstrated his electrochemical telegraph.

Alexander Bain

Bain (Image source: Wikipedia)

Keep in mind that Samuel Morse in 1843 was still building the first telegraph line between Washington, D.C. and Baltimore, and that few commercial telegraph lines were up in Europe.

The concept of the fax machine is pretty easy to work out: the transmitting machine scans a black and white image and sends an electrical signal indicating whether the part of the image it's currently scanning is black or white. A scanner on the receiving end, synchronized with the transmitting scanner, marks the paper according to the signal sent.

"Bain used a pendulum at the transmitter to provide an even scan across the image, with the image being moved forward by a small amount after each swing of the pendulum," writes Andrew Wheen in Dot-Dash to Dot.Com. "The image to be transmitted was copied to a sheet of copper and the white areas were etched away, leaving the black areas of the image standing proud of the surface. As the pendulum swung across the copper sheet, it completed an electrical circuit whenever it made electrical contact with one of these raised areas, and an electrical signal was sent down the line to the receiver.

Bain's electrochemical telegraph

A sketch of Bain's electrochemical telegraph. (Source: DigiCam History)

"At the receiver, an identical pendulum scanned across a sheet of paper soaked in potassium iodide, with the end of the pendulum making electrical contact with the paper. Whenever current flowed in the circuit, it caused a brown mark to appear on the paper. Since electromagnets were used to synchronize the transmit and receive pendulums, the position of each brown mark at the receiver corresponded with a raised area in the copper plate in the transmitter."

Of course, execution of the concept was not so easy. Bain's electrochemical telegraph remained an experimental project, and his patent for an improved version was not accepted as Frederick Bakewell had patented an "image telegraph" in 1848. Both produced poor-quality images and their transmitter and receiver devices had trouble synchronizing, so that neither were commercially viable.

Both inventions were completely outdone in 1861 by Giovanni Caselli's Pantelegraph. Caselli launched the first commercial telefax service between Paris and Lyon when the telephone as we know it didn't yet exist.

The traditional fax machine is transforming into a newer service known as FoIP (Fax over IP), championed by Max Schroeder, senior vice president at FaxCore. Fax still has a place in the business environment, Schroeder said in a discussion at the recent IT Expo in Austin, and is a reliable way to send and receive important documents.

Most recently, TMCNet noted, New Jersey residents affected by Hurricane Sandy had the option to use FoIP to send in their votes during the presidential election, in addition to email or mail-in ballot options.

From horse and buggy to the Internet age: That's a heck of a journey for a technology first conceptualized when telegraph networks were barely off the ground.