Yeah, I'm pretty sure its Borax... Caustic soda or sodium hydroxide. When combined with distilled water, it thickens (along with essential oil, this part of the process is called Trace), then saponifies (a molecular level activity!), becoming soap. After this point, most soap has to cure, but in the book I have, the soap is finished curing as soon as the soap is finished cooking. This book 'cooks' soap in an hour or so, instead of weeks for 'cold process'.

I meant to say before, I have heard the oatmeal in a stocking trick, but have never tried it. Even though it sounds good.