Admiralty Office, 28 Dec^r 1813

Sir

          I am commanded by my Lords
Commiƒsioners of the Admiralty to send
for your information the inclosed Copy
of a Letter, transmitted by Admiral
Sir Richard Bickerton, from Captain
Hollis of His Majesty's Ship Achille
relative to the Magnetic Influence
which appears to affect the Compaƒs
of Ships, owing to the iron Stanchions
which are placed on each side of
the Capstern [sic] to support the Centre
of the Quarter Deck. I am
        Sir     Your very humble Servt
                              Jn Barrow
Captain Flinders

[Captain Hollis' letter]

Copy               Achille Portsmouth 26 Dec^r 1813

Sir

I beg leave to state to you for the information of the Right H^ble the
Lords Comm^rs of the Admly that I have frequently, observed the
the Compaƒses of H M Ships which I have had the honor of Commanding
differ from each other, & very much from the Compaƒs which I always
carry on the Transom in the afterpart of my Cabin, as well as from
the one which I have on the Forepart of the Poop Deck, & the difference
is of course most when the Ship is sailing in an Eastern or Western direction.
    I am aware of what Captⁿ Flinders has written on this subject, but
I am of opinion that the principal cause of this attraction is owing to the
Magnetic Influence in this part of the Ship being conveyed to the
Three Quarter Deck Compaƒses by the Iron Stanchions which in
all Ships are placed on each side the Capstern to support the centre
of the Quarter Deck, it more particularly attracts the foremost of these
Compaƒses, which is the one the Ship is always Steered by when she is
not sailing by the Winds, when these Stanchions are trued up
they become in a manner neutralized, & I suppose only operates
as any other maƒs of Iron, so as to make the Compaƒses unsteady
but not to fix them — I have been led to make these observations
from knowing the Courses I had ordered the Ship to be Steered
& constantly remarking the difference between the Cabin Compaƒs
as well as of that on the Poop, & those by which the Ship was Steering.
    In sailing Westward down the Mediterranean & Eastward on
running for the English Channel the affect of some strong influence on
the Steering Compaƒses is always apparent, it must be always more