What is the early Chelsea “triangle” mark?

Many early Chelsea style wares, often dated to around 1745–49, are associated with an incised triangle, which the British Museum describes as an alchemical symbol for fire. The same museum record mentions an early object marked "Chelsea" and "1745", which supports the early location of the mark. Even with the triangle, the attribution can remain debated, as marks were copied and factories later produced Chelsea style wares. Consider the triangle as one of many clues, the tone of the paste, the appearance of the glaze, the family of the form, and the style of painting.