The Hot Water Battle as is known to-day was first patented by Croatian inventor Slavoljub Eduard Penkala in 1903. Incidentally, Penkala also was the first to patent the fountain pen. The concept of the Hot Water Bottle dates back to the 16th century. Early predecessors to the Hot Water Bottle, bed warmers, were constructed from metal, filled with embers from the fireplace, and used to heat the bed before retiring for the night.
Eventually, containers filled with hot water came into use. Unlike the bed warmer these containers; made from metals, glass, earthware, or wood and wrapper in cloth; could be kept in bed with the sleeper. It wasn't until the 1830's with Charles Goodyear's invention of vulcanised rubber that the modern Hot Water Bottle emerged.
Hot Water Bottles have all but disappeared now days. Since the late 20th century, with better heating and the invention of electric blankets and heating pads, the use of Hot Water Bottles has declined. Hot Water Bottles, however, have several advantages over more contemporary alternatives. For instance, Hot Water Bottles use no electricity and thus cost nothing to use and can be used when power is unavailable. They can also be used to sooth pain by applying heat to sore muscles.
So the next time you're shivering in your sheets, curl up with a Hot Water Bottle. They are available at most Drug Stores, but you can also find them on Amazon.com.