Annotation:
        N^o 21
Admiralty letter, with
others from Ad. Sir R.
Curtis and M^r Inman
April 27 1812

    Admiralty Office. 24th April 1812

Sir,

      In further answer to your
letter, of the 13 instant, containing
your observations with regard
to the variation of the compaƒs,
under certain circumstances
of situation, in the northern
and southern hemispheres,
I am commanded by my Lords
Commiƒsioners of the Admiralty
to transmit to you, herewith,
a copy of a letter, of yesterday's
date, from Admiral Sir
Roger Curtis, and of one
therein referred to, of the preceding
day's date, from Profeƒsor Inman
of the Royal Naval College at
Portsmouth, proposing a mode,
and mentioning the instruments
neceƒsary to ascertain the point
to

To Captain Matthew Flinders
    Admiral's Office
      Sheerneƒs

to which you have adverted; and
I have to acquaint you that directions
are given to the Navy Board
and to the Secretary of the
Board of Longitude to provide
the instruments required by
the Profeƒsor.
      I am,
          Sir,
              Your very humble serv^t
            Jn Barrow

[Mr Inman's letter]

          Royal Naval College
            22 April 1812
Sir,
      I take the liberty of suggesting to you that
the experiment about to be made on the horizon-
tal deviation of the Needle in different positions
of a Ship with respect to the points of the
compass, would receive, supposing such
deviations to exist, considerable elucidation
by determining the actual variation of
the compaƒs at the different Stations, and
also the dip of the Needle. It would
likewise be useful to observe on
Shore on the Same day, the diurnal
deviation of the Needle.
      For these purposes it would be
neceƒsary to procure Walkers Meridional
compaƒs, a Dipping Needle, and an
apparatus for observing the diurnal
deviation

Admiral Sir Roger Curtis B^t
            &c     &c     &c

deviation of the Needle.
      A Walkers Meridional Compaƒs may
be furnished from this Dockyard.
      A Dipping Needle must either be bought
of M^r Troughton Fleet Street; or furnished
by the Secretary of the Board of Longitude
at the requisition of the Lords Commiƒsioners
of the Admiralty, adjusted first for use
by M^r Troughton.
      An apparatus for observing the
diurnal deviation of the Needle may
be got from M^r Troughton.
      I have &c
          James Inman
          Profeƒser [sic] R N College