1776. Sunday. Jany. 28.
Mr. Upham informs that this Town of Brookfield abounds with a Stone, out of which Allum, Coperas and Sulphur are made. Out of one Bushell of this Stone, he made five Pounds of Coperas. He put the Stone into a Tub, poured Water on it, let it Stand 2 or 3 days, then drew it off, and boiled the Liquor away—let it stand and it shot into a Kind of Christals. Adding Chamberly1 and Alkaline Salts to the Coperas and that makes Allum.
We made some Sulphur, by Sublimation. We put 4 Quarts of the Stone into an Iron Kettle, laid a Wooden Cover over the Kettle leaving an Hole in the Middle. Then We put an Earthern Pot over the Top of the Kettle, and cemented it with Clay—then made a fire under the Kettle, and the Sulphur sublimated. We got about a Spoonfull.2
We have found a Bed of yellow Ocre in this Town. I got 12,00 Wt. We make Spanish Brown by burning the yellow Ocre.
1. Chamber-lye (variously spelled, 1500–1800): “Urine; esp. as used for washing, etc.” ().
2. JA could hardly have participated in these experiments, and so it must be assumed that this and the following paragraph are direct discourse by Upham. CFA supplied quotation marks around this passage.