Cold Particles

I watched a documentary once about the history of cooling and air-conditioning.  In it's overview of the ideas surrounding cooling, it mentioned that at one point people believed that there was a particle responsible for cold.  At first the mention of a "cold particle" sounds silly - obviously the temperature is based on the vibration and movement of molecules.  But when you stand in the cold and imagine it that way, it doesn't seem so far off.

On a related note, if I were to travel back in time to mid-1800's America, I would bring diagrams and instructions for how to build an air conditioner.  I would also need to build my own makeshift chemical batteries, but it would be worth it.  I could set up my own little shop with a room in the back where I would build the air conditioning units (and by that I mean hire people to build them for me).  It would be a humble little shop where I would also sell candies just for kicks, and many important businessmen and other wealthy individuals would visit in their top hats and business attire to buy my AC units.