The Making of the Glencairn Methuselah Window: Page 14

<fig 6 illustration of text below>

Take a porcelain crucible. <punctuation per scribe> Arch two pieces of lead on top of it. Put thin turpentine in – cover with a rag to keep dust and dirt out but letting the air in. Stir thoroughly three times a day – It took 19 days, stirred 42 times

Color in jar pale greenish
The above produces a sticky medium which is slow drying