Thanks for the links MikeMl...
Yes you are absolutely correct: I DO NOT understand Ohm's law very well - that's why I came to this forum to ask questions. It's been 30 yrs since I studied basic circuits in college physics - and with regard to electronics, I'm not afraid to state I'm rather dumb!
But I'm a good experimentalist, and I know that the system I am investigating is NOT a simple problem. I dont just have '4 lamps powered by a battery'. In my case, the line voltage (mains) to the power supply fluctuate; the resistance in each lamp changes with temperature, and with age; transmission through the quartz glass envelope changes with age; resistance in the lamp connections changes due to long term corrosion; etc. etc. Life is not simple!
I understand spectroscopy, but not electronics. What I'm asking for, is a little simple advice on 'what makes a good power supply' for my application. When someone says to wire the lamps in series, I want to understand WHY this is suggested - what are the subtle physical / chemical changes to devices that would cause someone to recommend one circuit over another (serial vs. parallel). Sure I can read, read, read... but it's a lot more sensible to broadcast questions to experts!
If someone has some really PRACTICAL knowledge to contribute, I would appreciate it. Thanks a bunch...
HyperB