IIRC - The (watch-size) "Pocket Oilers" are mentioned in one of 'The Chief of Ordnance - Annual Reports'. The need for more oil became apparent during tropical campaigns.
The 'Brophy page' above, says they were intended to be carried by Sergeants and contained Sperm Whale Oil.
The very common Krag 'cartridge-size' Oil-Bottle was carried in altered rifle & carbine butt-traps. For Krags lacking a butt-trap, it was carried in a Mill's Belt cartridge loop.
These smaller capacity oil-bottles were described, in 'Annual Reports', as containing cosmoline-oil.
The 'Brophy page' above, says they were intended to be carried by Sergeants and contained Sperm Whale Oil.
The very common Krag 'cartridge-size' Oil-Bottle was carried in altered rifle & carbine butt-traps. For Krags lacking a butt-trap, it was carried in a Mill's Belt cartridge loop.
These smaller capacity oil-bottles were described, in 'Annual Reports', as containing cosmoline-oil.

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