In the year 1807, three diplomatic instruments were signed. They have
caused unnecessary confusion. On the 28th January, 1807, General
Hutchinson signed a Treaty of Peace with Prussia; on the 26th April,
1807, Alexander and Frederick William signed the Convention of
Bartenstein, to which Great Britain and Austria were invited to
accede—an invitation which both declined; on the 27th June, 1807,
Canning and Jacobi-Kloest signed a treaty of subsidy, before the
exchange of ratifications of which, Tilsit changed the whole
situation, and so it was not ratified. Apart from rectifying
misstatements which have found their way into authoritative works, the
question is not without importance. Canning would not subscribe to the
vague commitments of Bartenstein, which foreshadowed the settlement of
1814, but would conclude, on the other hand, treaties of subsidy for
the prosecution of the war.
Now Colonel Lloyd (“Cambridge Modern History,” vol. IX, p. 289) states
that on 27th June, Great Britain acceded to the Convention of
Bartenstein, undertaking to pay a subsidy of £100,000 to Prussia in
the course of the year. He thus confuses accession to the Convention
with the treaty of subsidy. Dr. Rose (“Cambridge Modern History,” vol.
IX, p. 296) states that Britain “became a party” to the Convention. In
the “Cambridge History of British Foreign Policy” (vol. I, p. 356) he
writes that “she soon acceded to it.” Garden (“Histoire des Traités de
paix,” vol. X, p. 200) writes that she “s’empressa d’accéder à la
Convention.”
On 29th June, 1807, Jacobi-Kloest, the Prussian Minister in London,
officially communicated the Convention to Canning and announced that
he had full powers to sign an act of accession with a British
plenipotentiary (F.O., Prussia, 77). On the same day, D’Alopeus did
the same thing and declared that “Son Excellence M. Canning, ayant
déjà _fait connaître au soussigné les dispositions de son auguste
souverain de concourir à l’accomplissement de l’important objet que
les hautes parties contractantes ont en vue_.” (F.O., Russia, 73.)
Matters did not go beyond that stage. The Treaty of Tilsit was
announced officially on the 1st August (D’Alopeus to Canning, 20th
July-1st August, 1807, F.O., Russia, 73). In his answer to this
communication, Canning expatiated on the dispositions of George III
and adduced as a proof “_the willingness expressed by His Majesty to
accede to the Convention of Bartenstein_.” (Canning to D’Alopeus, 5th
August, 1807, F.O., Russia, 73.) It was now too late.