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    A lunars tale from the 1840s
    From: Frank Reed
    Date: 2008 Mar 21, 06:19 -0400

     From "The Nautical Magazine" 1845, via google books...
    
    Under the title,
    "CHRONOMETERS AND LUNARS,"
    
    After a preamble offering some revised positions for islands and points in
    the Indies, the author writes:
    
    "I would now beg to offer some remarks relative to chronometers, and the
    fearful consequences that may arise if we place too much confidence in them,
    which from their beautiful and improved construction we are now too apt to
    do, and neglect those observations of the Heavenly bodies (which can only be
    of use by their being in constant practice) when you may have confidence in
    them.
    
    On my outward voyage, I had a beautiful watch of Murray's, which differed
    only nine seconds, in my run from Portsmouth to the Great Ladrone (on the
    coast of China). I placed great reliance on this watch during my homeward
    voyage, after leaving the coast of Java, and as soon as the moon came in
    distance I obtained a few sets of sights which gave the watch a considerable
    error, nearly three inmutes. At this time I imagined my distances must have
    been incorrect, but the day previous to getting on the L'Agulhas bank, and
    in a run of about thirty days from Java Head, I was fortunate enough to get
    the mean of some thirty or forty distances, and I was much astonished that
    they gave the watch an error of ninety miles to the westward. I also
    carefully observed the sun's semi-diameter, and this corresponding with the
    Nautical Almanac, gave me confidence in my sights, and shook my confidence
    in the chronometers. It also fortunately placed me on my guard, and as on
    rounding the land, I was in a position to make Cape L'Agulhas at daylight I
    did not bear away. I was running nine knots at the time, with a strong
    S.S.W. wind, and did not see the Cape until 2 P.M., having run since
    daylight about 80 miles departure, which made the lunar sights as near
    correct as I could take the bearings of the land, at about four leagues
    distance in hazy weather. Had I been by chronometer, near the longitude of
    the Cape in the evening, I certainly should have borne away before morning,
    and had I done so, the melancholy fate of the ship which I commanded would,
    I fear, have been similar to the Arniston, Northumberland, and various
    others.
    
    How to account for this error in the watch has quite bewildered me,
    excepting it arose from magnetic attraction, as from some cause or
    carelessness a brace of pistols was placed close to the watches, which I had
    removed, directly I found the watches had altered their rates. The
    chronometer has since remained stationary, and retains the same rate as when
    I was off the Cape.
    
    On my passage towards England, after rounding the Cape, I took every
    opportunity of obtaining lunar distances ; and two days before I reached St.
    Helena, I spoke a ship which had also seen Cape L'Agulhas, and we differed
    seventy miles in our longitude. This startled me. But when I found my
    brother mariner had not taken any lunar sights, and having confidence in my
    instrument, I steered boldly for the island, and made it ahead about an hour
    before daylight.
    
    I was at St. Helena two days. Each day I got the Greenwich time from the
    observatory, and in taking the mean of my lunars about 100 distances, I was
    much pleased to find we only differed one second from each other.
    
    I would from these circumstances caution mariners, not to be too confident
    in their chronometers, and to lose no opportunity of obtaining lunar
    observations when practicable, and which I fear is now too much neglected,
    and which unless they are constantly practised can be of little avail, and
    can give no confidence to the observer. I have generally rated my
    chronometers by lunars, and have hitherto been fortunately correct in doing
    so, as they seldom retain the rate given by their constructors, and having
    two sextants, one of which being Troughton's, which as an instrument of
    confidence for navigation, is worth to me all the chronometers that were
    ever constructed.
    
    I have once before made some small contribution to your work, and am a
    subscriber from its commencement, and many an agreeable hour, I spend at sea
    in conning over its pages. Should yon think this worth inserting, or any
    part of it in your publication, I beg you will do so.
    
    I have the honour, &c.,
    T. N. WERE,
    Commander of the Ship City of Derry. "
    
    Some good stuff in there from the final decade of lunars...
    
     -FER
    
    
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