RE: VMs: Declaration of WAR against EVA

["Don Latham" <djl@xxxxxxxxxxx>]

Nick:
I have seen drawings of the "windmill" structures with big "arms" that were
semaphores, even learned the rudiments of semaphore in the boy scouts.   Did
not know thwere were codebooks, but of course there would be!
Don

-----Original Message-----
From: owner-vms-list@xxxxxxxxxxx [mailto:owner-vms-list@xxxxxxxxxxx]On
Behalf Of Nick Pelling
Sent: Thursday, March 06, 2003 2:02 AM
To: vms-list@xxxxxxxxxxx
Subject: RE: VMs: Declaration of WAR against EVA


Hi Don,

At 01:30 06/03/03 -0700, Don Latham wrote:
>heck.   Forgot to mention.  Even though Morse was optimized for English,
>(etaoin shrdlu) the cost of telegraph was high enough that elaborate
>codebooks were generated to cut the cost of telegrams.  The books were not
>particularly secret, and were to some extent business-type optimized. I
have
>3 or 4 of these.

Have you ever seen any of the codebooks for optical telegraphy? This was
first used on 11am, March 2, 1791 - the local doctor chose the phrase: "Si
vous reussissez vous serez bientot couvert de gloire" ("If you succeed, you
will soon bask in glory") - and was transmitted over roughly 16km.

Mechanically, it consisted of two rotating indicators: according to
Scientific American (Jan 1994), the codebook of 1795 contained 92 pages of
92 entries each, for a total of 8464 letters, numerals and phrases, with
the 92 most common phrases on the first page of the book. Then, in 1799,
the inventor extended the code with two extra books, giving a grand total
of 25392 entries.

The Swedish optical telegraphy system (dating from 1795) had 10 shutters:
its codebook had 13 tables, allowing 5120 different signals. The motto of
the Swedish Telegraph Corps: signal 636 (Passa val upp, or Be On Guard).

Here in the UK, the Admiralty built lines from London to Portsmouth,
Plymouth, Yarmouth, and Deal between 1796 and 1816 (there are several
semaphore tower sites fairly close to where I live).

The last three optical telegraphs in Sweden were closed in 1881.

Morse code? Pah! :-)

Cheers, .....Nick Pelling.....

PS: Edelcrantz (the Swedish optical telegraphy inventor) wrote in his
"Treatise on Telegraphs" (1796): "It often happens, with regard to new
inventions, that one part of the general public finds them useless and
another part considers them to be impossible. When it becomes clear that
the possibility and the usefulness can no longer be denied, most agree that
the whole thing was fairly easy to discover and that they knew about it all
along." :-)

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