Just bought a Coleman 238A

What an exciting acquisition, @phaedrus42 .
@george , in my personal opinion, it was made to combined the best features of the 237 and the Petromax.
I believe Mr. Tullis designed some of the best lanterns ever produced by Coleman, such the iconic 242, which apparently spawned similar ones such the 249, 236 and 237. One of the objectives, if I remembered correctly, was for the reduction of cast shadows by the rods of the frame cage.
And if I've not mistaken, one of the 238's featured designs came with an extra large, straight generator with numerous horizontal ribs/fins (something like a Ditmar/Maxim). That could be to compete with the very efficient Preston loop vaporizer, which was superior to a plain straight tube (more surface area for heat transfer, less coking of the fuel, etc).
I believe they're made to safely and efficiently burn both gasoline/white gas and kerosene.
Perhaps, the amount of extra brass and the additional machining of the fins proved too uneconomical for serious competition. It could be they eventually settled down on a Preston loop instead(once the Graetz patent expired, of course).
For the size, maybe supposedly to 'outshine' the Petromax? Or perhaps to dissipate the greater heat produced to avoid the fuel in the fount from reaching boiling temperatures especially when using gasoline?

 

@Wim I guess that Belgium like Holland has a civil defence.
They ordered a lot of lanterns and stoves from various brands to stock them in case they would be needed. Luckily there was no need, so these stocks come on the market as NOS.

 

Wish they were NOS sold over here! Not that lucky...

 

Wow!
Superb.