While we now enjoy them as a decoration in our homes, candles were a necessity in the days before electricity was a common feature of the home. Prior to the development of kerosene, most lighting was provided by candles. When the supply of candles  dwindled, tin moulds like this one would be used to make a new batch. Up until about the 1850s, candles were made using clarified animal fat called tallow. This would be done by first boiling meat over a hot fire, to separate the animal fat from the meat and bones. When the fat became liquid it would then be poured into the mould. A wick would need to be inserted through the hole at the top of the mould before the tallow could be poured into it. After the tallow had set hard, up to a day later, the candles would be released from the mould by dipping in hot water and be ready to use. 

Unfortunately, tallow melted quickly and gave off an odour of rancid meat as it burned, so paraffin wax with stearic acid was used once it became more readily available in the late 1800s. Despite the eventually use of kerosene lamps, candles continued to be made in rural areas well into the early 1930s, as they were a much cheaper alternative to buying fuel for lamps.  (californiamuseum.org, collection.mass.museum)