This is cool, and ancient, I think I will try to make one.

Ancient but new to me.

Good find 

I'd really like to make one of these as well. If possible, I'll try to find a tall, thin graduated beaker to use, rather than a mason jar. Of course, I have LOTS of mason jars (Grandma did a lot of canning, years back), but I think a tall vessel would look far cooler.

Potassium Nitrate is Salt Petre, Ammonium Chloride is used for cattle and (weirdly) fish, and found this Camphor from Amazon.

As for 50% ABV vodka...

Looks like a fun project. Please post if you do this and how easy it is to get the bits.

I've found the Ammonium Chloride locally for around 10 quid for FAR more than I'll ever need, and the saltpeter should be obtainable at the local nursery for cheap. the vodka I can get at work, and the Camphor is available at Tractor Supply, just down the road from work. All I need now is a nice graduated flask and a stopper for it. Here's what I want to get for the flask:

http://www.ebay.com/itm/1000mL-Graduated-Cylinder-Rouond-Base-Borosilicate-Glass-1000-mL-1-Piece-/231880748604

The stopper should be fairly easy to get.

  It all sounds pretty good Dave and I'd agree a flask would be nice,  I like the idea but I don't like the idea of putting a glass container outside since the air conditioner would ruin everything.  Good luck with it
Carl2