§ 63 The Wax Melted Out
This done, the worker proceeds to apply heat to the said mould equally all over, so that it may become united and little by little be warmed through, and he increases the heat till the mould is thoroughly hot throughout, so that the wax which is in the hollow space becomes melted and all flows out at the spot through which the metal is to be poured, without any particle of the wax remaining within.177 To be sure of this, it is needful, before the pieces of wax are grafted in to their places on the figure, to weigh them piece by piece; in the same way after drawing out the wax, it must be weighed again, when by making the subtraction the artist sees if any wax be left between the core and the mould, and how much has come out. Notice that the skill and care of the artist is manifested in the process of taking out the wax; herein is seen the difficulty of producing the casts so that they come out sharp and beautiful, for if any of the wax be left, it would ruin the whole cast, especially that part where the wax remains.