Name: 視覺電報 (錢幣的語言：5/16) (Visual Telegraphs (Language of Coins: 5/16))
Uploaded: 2021-01-14T04:33:31.000Z
Duration: 9 min 20 s
Description: 【看影片學英語】數萬部 YouTube 影片，搭配英漢字典即點即查，輕鬆掌握單字發音與用法，長久累積看電影不必再看字幕。

The signal fire is no doubt one of the oldest technologies

perhaps dating back to the first controlled use of fire.

It allows one person to influence another's belief state --

either the presence or absence of something,

we are able to switch between one of two belief states.

we find that this was of great importance to military powers,

which all rely on effective communications.

And Greek military history provides clear evidence

of the first advancements in communication,

Polybius was a Greek historian born in 200 BC.

He wrote 'The Histories,' which is a treasure trove of detail

related to the communication technologies of the time.

He writes: "The power of acting at the right time

contributes very much to the success of enterprises.

And fire signals are the most efficient of all devices

However, the limitation of a signal fire was clear to him.

"It was possible for those who had agreed on this

to convey information that, say, a fleet had arrived.

or a massacre having taken place in town --

things that often happen, but cannot all be foreseen --

all such matters defied communication by fire signal."

the space of possible messages is small --

such as 'enemy has arrived' or '[enemy has] not arrived.'

which is the total number of possible messages -- [grew],

[so grew the] need to communicate [more] differences.

And in The Histories, Polybius describes a technology

one of the earliest Greek writers on the art of war --

And his technology was described as follows:

And through the middle should pass a rod,

which [contains] the most common events that occur in war.

To communicate, they would proceed as follows:

and they would both begin to drain their vessels

from a bored hole of equal size at the bottom.

to signal that they should both stop the flow of water.

used differences in time to signal messages.

However, its expressive capabilitiy was limited,

Polybius then writes of a newer method --

which he claims was "perfected by myself,

and quite definite and capable of dispatching --

His method -- now known as the 'Polybius Square' --

each have 10 torches -- separated into two groups of five.

from each group of torches -- and raises them.

the number of torches lit in the first group.

signifies the column position in this grid.

The intersection of the row and column number

字幕列表影片播放

視覺電報 (錢幣的語言：5/16) (Visual Telegraphs (Language of Coins: 5/16))

demonstrate

realize

position

method