Annealing
If left to cool at room temperature, the glass would fracture and break from the temperature difference. All piieces even the marbles are annealed overnight to prevent breaking. Globes are easy to insert in the annealing oven, using a hook, vases and other pieces have to be carried and places in using a pair of oversized kevlar mittens. Once in the annealing oven the temperature is brought down slowly overnight from a temperature of 475 degrees celsius to room temperature.
