I have an air guide compass mounted on the dash of my boat. I got it from my dad who bought it around 1965. The problem I have with it is that the fluid level inside is to low for the compass to move correctly. What do I add to it and how? There are two small plastic screws in the botton, one says ew and the other says ns. I am assuming those are for adjusting the compass, but can fluid be introduced into the inside at that point?

I doubt that you'll be able to add any fluid, even if you knew what to add.