The Practical Telegraphist  is a translation by Chris Rutkowski, NW6V, an American expert on CW telegraphy, of a book written in 1851 by Clemens Gerke, an ‘Inspector of the electro-magnetic telegraph at Hamburg’.

Gerke is of international importance, as he re-wrote Morse’s arrangement of the code into a version very similar to the current International version of the Morse alphabet.

The book is 100 pages long and some of the translation (or maybe the original text) is idiosyncratic – for example, we are told that they put condoms on the bottom of telegraph poles as, ahem, a preservative!

The translation mainly uses American units (inches and miles): it is not clear whether the original used metric units, which were becoming universal in Europe at that time, but a variety of other units occasionally appear, perhaps where Gerke used traditional units of uncertain value.

Gerke’s telegraph was a considerable undertaking, running from the coast at Cuxhaven to Hamburg, a distance of 130 km or 80 miles, via intermediate stations. There was also a line from Hamburg to Berlin, 290 km or 180 miles.  He mentions other telegraphs that had been spreading everywhere over the preceding ten years, along with the development of the railways, so there was a significant network by 1851.

Electro-galvanic Batteries

The first chapter describes in detail the construction of ‘electro-galvanic’ batteries for use in telegraphy.  These make use of quite dangerous chemicals like hydrochloric acid, sulphuric acid, nitric acid, mercury, with plates made of zinc and copper for the electrodes.  He preferred the ‘Daniel Cell’ where the inner negative pole is a copper cylinder housed inside a porous clay pot (best made in the royal porcelain factory in Berlin), filled with copper sulphate solution.  The outer pole is a zinc cylinder surrounded by salt water or dilute sulphuric acid and the whole is contained in a ‘strong beer glass’! (They must have liked their beer, because the glasses were about 4 inches in diameter and filled 5 inches high!)

This cell produces an EMF of about 1 volt, and he makes it clear that you need several of these ‘side-by-side’, connected in series, but it seems that the exact number required was a matter of some trial and error.  He recommends that batteries are installed in series at both ends of the line to ensure there is enough power for the writing machines.  It seems that often a sensitive relay (hitherto a secret revolutionary device) was installed in the line and the relay then drives the writing machine with power from the local battery.

Insulation

A big headache was to obtain reliable insulation of the line.  Most of the line was carried on the pine telegraph poles with which we are familiar, 23 feet above the ground and 150 yards apart, and using glass insulators.  However, these were prone to cracking or to damage from small boys throwing stones at them!  Where it was necessary to use an underground line, usually the copper line (stated to be almost ¼ inch diameter) was carried inside a metal tube filled with gutta-percha, a type of latex.  Gerke gives a lot of detail about how to preserve this material from degradation, which was a serious problem.

Writing Instruments

Much of the rest of the book deals with the arrangement of the telegraph lines and setting up the ‘writing instrument’ which used a stylus depressed by an electromagnet to impress indentations on a paper tape.

Telluric Activity

The system suffered greatly from interference which he largely attributes to  ‘telluric currents’, because they only use a single wire to connect telegraph stations, with the return path being via the ground.  I had not appreciated that natural ‘telluric currents’ flow through the ground, being induced by lightning, the earth’s magnetic field and other effects. The telegraph uses low voltage and current, so it does not take much telluric and atmospheric influence to upset the delicate balance of the electromagnets in the telegraph’s detectors.  Gerke makes it clear that a principal skill of a telegraphist was to constantly adjust the balance of the detectors.

Instrumentation was at best crude and in many cases he suggests touching the ends of the wires to the tongue to detect the presence of galvanic fluid.

Improving the code

The problem with Morse’s (or same say his colleague Vail’s) version of the code was that some characters used longer than standard dashes, whilst others had gaps between the dots.  Moreover, some letters important in German (especially umlauted ä, ö and ü) had no corresponding code  The variable-length dashes and the intra-letter pauses were both difficult to key and susceptible to misinterpretation especially on a noisy line.

A Professor Steinheil (who constructed several railway telegraphs in Germany) devised an alternative code which used fewer elements (dots and dashes) and avoided the intra-letter spaces of Morse’s, but it had several serious defects.  In particular, it used the same code (––·) for letters c, k and q,  the same code for (–·) for d and t, and the same code (–··) for f, v and 5, whilst omitting codes for the umlauted vowels, for x and for y.  Gerke says this is because Steinheil never wanted to use more than four elements in each letter.

Gerke’s version of Morse Code

Gerke says that his code, largely the same as Morse’s, includes all the letters, including the umlauted vowels important in German, whilst overall not needing more bits of time than Steinheil’s.  Moreover, he says, he took into account the frequency of use of letters (from consultation with typesetters), which had not been considered by Steinheil, and that in practice it would be faster to write using his code.  Although he doesn’t say how many words per minute his telegraphists could accomplish, he says that this was as fast as ordinary writing with a pen (which is typically 13 to 20 wpm) and therefore quite sufficient.

The current International Morse Code is almost the same as Gerke’s.  He kept Morse’s codes for the digits, whilst the current International code use a more consistent and logical arrangement.

Interestingly, Morse, Steinheil and Gerke all omitted letter I: the current code for I is what they used for J.  Some other letters were changed for the current code, including O, P, X, Y and Z.

Conclusion

The Practical Telegraphist is now only of historical interest.  In the 1850s, they lacked much in the way of instruments, which greatly hampered their work – much investigation relied on experience, trial and error,  and testing with the tongue – but it is fascinating to see how our knowledge of electricity has developed whilst the telegraphist’s art is much the same.