There is only one reason for posting this stove here, and that is that I cannot explain what it is or why it exists. A 3-leg 2 pint Optimus No.10 is nowhere to be found listed in any of the catalogues currently to be found in the library. BUT IT CLEARLY DOES EXIST. All of the visible features place it as being from the 1920s. But all of the visible features bar one make it identical, as far as I can see, to a standard Optimus No.1 of that period. So why is it given the model number '10'? What am I missing? The only feature not common to the No.1s that I can see is the dimpled spirit cup with auto-light flame leader (part no.293a in the 1929 catalogue). OK so those are normally found on silent burners, and in fact are pretty pointless on a 'roarer', but that surely isn't sufficient to give it a new model number even if it is original. What am I missing? Why is this a '10'? when was it made? and why?