The hot water bottle consists of two thin glass shells that drain air between them and coat one side with a thin layer of silver. A hot water bottle has a much thinner opening than its "body" and can be corked.
- Sep 21, 2019-
The hot water bottle consists of two thin glass shells that drain air between them and coat one side with a thin layer of silver. A hot water bottle has a much thinner opening than its "body" and can be corked.