FIRST EXAMPLE (1922):
Stampings:
[S1] Ao [---] DUNHILL [‘D’with tails /] LONDON [shorter then ‘dunhill’]
[S2] MADE IN ENGLAND 2 [/] "INNER TUBE" [/]PATENTED MARCH . 9 . 15 [---]173 [/] EX.
Picture:
[note, I believe the ‘ex’ stamping indicates a pipe given in 'exchange' under the then new Dunhill guarantee as this is the standard stamping later used by Dunhill for exchanged pipes..]
Picture of another pipe (a model '59') with identical nomenclature except of model number and 'ex':
SECOND EXAMPLE (1922):
Stampings:
[S1] Ao [---] DUNHILL [‘D’with tails /] LONDON [shorter then ‘dunhill’]
[S2] MADE IN ENGLAND 2 [/] "INNER TUBE" [/]PATENTED 1914 [---] 115
Picture:
[note, the Canadian inner tube patent 158709 was granted December 3, 1914.]
THIRD EXAMPLE (1922):
Stampings:
[S1] DR [---] DUNHILL [‘D’with tails /] LONDON [shorter then ‘dunhill’] <>
[S2] "INNER TUBE" [/]PAT. No 5861/12 2 [---] 24
Picture:
FOURTH EXAMPLE (1922):
Stampings:
[S1] A [---] DUNHILL [no 'd' tails /] LONDON [shorter then ‘dunhill’]
[S2] "INNER TUBE" [/] PAT. No 5861/12 2 [---] 315
Picture:
FIFTH EXAMPLE (1923):
Stampings:
[S1] Ao [---] DUNHILL [no 'd' tails /] LONDON [shorter then ‘dunhill’]
[S2] MADE IN ENGLAND 3 [/] "INNER TUBE" [/] PATENTED MARCH . 9 . 15 [---] 137
Picture:
SIXTH EXAMPLE (1924):
Stampings:
[S1] Ao [---] DUNHILL [no 'd' tails /] LONDON [shorter then ‘dunhill’]
[S2] MADE IN ENGLAND 4 [/] "INNER TUBE" [/] PATENT No 1130806/15 [---] 60
Picture:
NO EXAMPLE OF A 1925 PIPE