Welcome to the NavList Message Boards.


A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Add Images & Files
    Transatlantic cable
    From: Alexandre Eremenko
    Date: 2005 Jun 2, 04:20 -0500

    This topic is out of the scope of the list
    but I want to correct some statements.
    First of all, Thomson's name was William
    (not David!) and this is the same Thomson
    who later became Lord Kelvin.
    After the first cable failed, the scientific
    consultant was replaced by Thomson.
    The main reason of the first cable poor characteristics
    was its design. Physicists and engineers of that time
    poorly understood physical and mathematical principles
    involved, and even Faraday supported the wrong views
    on this cable design.
    The necessary theory contained in the book of Joseph
    Fourier, published around 1830. W. Thomson was one
    of the few physicists/applied mathematicians who
    read and understood this book.
    I do not want to include mathematics here,
    but a good sorce for the whole story (of the transatlantic
    cable design) is the
    book of T. Korner on Fourier Analysis.
    I lecture on this from time to time to
    my students and plan to add this lecture to my
    web site sometimes.
    On Wed, 1 Jun 2005, Lu Abel wrote:
    > Gentlemen:
    > The first cable was plagued with inadequate insulation, resulting in
    > frequent bouts of not quite short circuits but signal losses so great
    > that telegraphic characters were often simply not received at the far
    > end.  It was this that led to it requiring "several hours" to transmit a
    > telegram.
    > "Spreading" of electrical signals takes place when a medium (such as a
    > cable) can not transmit the high frequency portion of a signal.  An
    > on-off pulse, such as a telegraphic character, theoretically includes
    > signal components of very high (indeed, infinite) frequencies.   But the
    > speed of transmission is still the speed of light.  Thus a nice sharp
    > pulse transmitted on one end of the cable might arrive as a smeared-out,
    > possibly unrecognizable mess -- but it would travel across the Atlantic
    > (and therefore arrive) in a fraction of a second.

    Browse Files

    Drop Files


    What is NavList?

    Join NavList

    (please, no nicknames or handles)
    Do you want to receive all group messages by email?
    Yes No

    You can also join by posting. Your first on-topic post automatically makes you a member.

    Posting Code

    Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.

    Email Settings

    Posting Code:

    Custom Index

    Start date: (yyyymm dd)
    End date: (yyyymm dd)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site