Questions about Plinius\' Naturalis Historiae Book 34

[lup_alb]

The quality of watter does influence the quality of the iron objects quenched in it. That's why some blacksmiths in Romania (and also there are references for medieval smiths doing this) put pieces of raw leather and other substances I can't remember in the quenching barrel and let them there for a period, making a sort of "soup" in which they quench the objects.