Food Warmers (aka: pap warmers, tea warmers and/or milk warmers)
Food warmers, unlike their French counterparts (known as "veilleuse"), generally came in five sections: (1) the base; (2) the insert (holding the warm water); (3) the porriger (or teapot)(that sits in the insert); (4) the lid of the porriger (or teapot) and (5) the small cup that sits in the base and holds the candle, etc. I say "generally" because I have seen some food warmers where the porriger fits so exactly in the base that is it hard to imagine there actually being an insert involved (see the bottom right photo above - it does not have an insert). The French equivalents generally did not have inserts and the burning cups were not round but oval or rectangle in shape.
The food warmer (below left) is a Samuel Clarke's Pyramid Food Warmer. One item that is missing from the picture that should be included is of course a Samuel Clarke's Pyramid candle that goes on top of the small ceramic dish in the holder and that the glass lamp shade covers. Clarke's made its own candles, that is why I mention it missing. Also note that I recently acquired the glass shade which I presently have a close up of in the new items section.
When sold the Wedgwood food warmers "I am told" came with two tops (as shown above) one for water/tea and one for food.
When collecting English food warmers parts separately please note that even though they look the same and are made by the same manufacturer they actually came in different sizes and did not all fit together. For instance the two porrigers below (right) are both Wedgwood and look exactly the same but as you can see they are slightly different in size which makes all the difference in the world when trying to fit them together. When putting individual parts together also note that (1) the parts should be the same color (they range from white to yellow-cream) and (2) that there should be very little play (back and forth movement) when putting the parts together. All the complete sets that I have seen fit very nicely (and snugly) together.
Please look at the Photo Library as it contains a few wonderfully representative samples to enjoy and study.