If I'm right, a H33 ballast can light it up (or even better, a period-correct H1 ballast!)

sorry for not getting back sooner....gtreat find, yes 400 watt '- ballst will work just make sure its mounted base up as it says on etch....and for date code, im no expert but using edcuated guess and my lamp as reference the 52 would be April 1944

Yeah 4/44 sounds about right. Nice find Henry!

I think this lamp can also be operated on a simple european reactor ballast for 400 MB mercury lamps because the voltage and the current of this MA lamp, as well as all MA lamps, are the same as MB high pressure mercury lamps.

this is a Medium Pressure Mercury Lamp which uses a Glass Arc Tube, instead of a Quartz Arctube, as the Lamp Voltage is 130 volts 3.12 amps you can use standard 400w Mercury Ballast to light you lamp, if you don't have one you can use a M59 Metal Halide Ballast without the Ignitor

Re the Date Code I have it as April 1946 based on the ILE Codes

Yes you can light it on a modern H-33 mercury ballast, just be sure to operate it in the correct burning position as marked on the lamp etch. Colin, it is indeed April 1944, you must have followed the British system that is off by a couple years.

Hey guys, thanks for all the great info!!!!! This lamp does have a steel base (magnetic) which would be correct for war time production. I'm gonna post some lit pics.