So to all those people who guessed correctly, this month’s mystery item was a hot water bottleWe still use hot water bottles today, however they are now made of rubber or pvc to a design patented by the Croatian inventor Eduard Penkala. This was his first invention and consisted of a resin bottle filled with hot water, which was to be used in bed on cold nights. Hot water bottles also now have competition from microwavable heat pads and the electric blanket.
However the hot water bottle has had a long history.....
The earliest example of a hot water bottle is the bed warming pan, which dates back to the 16th century. Embers from the fire were placed into this metal pan with a lid and slipped in between the bed sheets. The long wooden handle provided the user with a way of moving the pan, and the heat, across the bed.
Next in the development of bed warming equipment came the stoneware hot water bottle, as can be seen in the image below. This is cream and brown glazed ceramic example, and could be used in bed or carried on journeys. This example is 26cm long and is fairly heavy, even more so when it was filled with water! This bottle is for the feet, its flat base allows it to stand upright easily either in bed or a carriage.
Original Victorian Hot water Bottle. 
The example at the Museum of Dartmoorlife is earthenware and comes with a metal carrying handle and screw stopper. It measures 23 cm high. As can be seen on the bottle itself, it is 'The Adaptable Hot Water Bottle and Bed Warmer', and was made at Old Fulham Pottery. The instructions for use are clear and easy to follow, ensure the bottle is warmed first and them fill with boiling water.
Museum Hot Water Bottle
 Object Lessons, 'Stone Hot Water Bottle', 2012. [Online] Available from: www.objectlessons.org/houses-and-homes-victorians/stone-hot-water-bottle-victorian-original/s59/a274// (Accessed 26/03/2012).
 Object Lessons, 'Stone Hot Water Bottle', 2012. [Online] Available from: www.objectlessons.org/houses-and-homes-victorians/stone-hot-water-bottle-victorian-original/s59/a274/. (Accessed 26/03/2012).