Thomas Jefferson Papers

Notes on Potash and Pearl Ash

Notes on Pot and Pearlash.

a man will cut and burn 2 ½ cords of wood a day.

a cord of wood yeilds 2. bushels of ashes. [neither pine nor chesnut will do]

a bushel of ashes sells for 9. cents.

it will make 6. ℔ of brown salts, which make 3 ℔ to 5 ℔ pearl ash in the common way and 5. ℔ of pearlash in Hopkins’s way.

for a small work, 2 kettles suffice to boil the lie into brown salts and 1. to melt up the brown salts.

¼ cord of wood a day maintains one fire, which will do for 5. kettles.

to keep 3. kettles a going will require the attendance of a man and boy.

there should be 15. or 16. tubs of 100. bushels each.

3. kettles will turn out 1000 ℔ of pearl ash a week.

consequently will require 100. cords of wood a week and 7. cutters to keep them constantly at work.

each kettle costs 24. Doll.

Potash is worth in England the ton, and in America 114⅔D.

Pearlash is worth in England £40. sterl. and in America £40. lawful.

An estimate of the profit and expence of such a work at 3. ft pearl-ash to the bushel of ashes, which is 100. ℔ pearlash a day. And counting 5. days to the week, which would give only 500 ℔. of pearl ash a week, instead of 1000. ℔ the common calculation.

 £ 500 ℔ of pearl ash a week, is 13. tons a year, @ £40. Virga. currcy. 520– 0–0 £  s  d 7. cutters hired @ £12. a year, adding maintenance and clothing 128–16–0 a manager for his hire and provisions 50– 0–0 a boy 10– 0–0 implements annually 10– 0–0 a waggon, team, and driver, all expences included 111–15–0 310–11–0 Clear profit in cash 209– 9–0 [@ 4 ℔ pearlash to the bushel, (a very moderate calculation) it would add 5 ton a year, worth 200£. @ 5. ℔ to the bushel £400.]1 520– 0–0 add to this the clearing 150. acres of land a year, whatever it is worth.

Note. I was told by Hopkins that ashes burnt in the open field cannot be made into pearl ash in the common way: but answer well for that in his way. This, if certain, is a very important circumstance in Virginia.

(: Stuart Papers); entirely in TJ’s hand; undated; brackets in original. (); endorsed in ink by TJ.

These notes follow closely a similar calculation in TJ’s Farm Book ( description begins Edwin M. Betts, ed., Thomas Jefferson’s Farm Book, Princeton, 1953 description ends , 117). For Hopkins’s way of making potash and pearl ash, see Samuel Hopkins to TJ, 27 June 1791, and note.

1Bracketed text inserted by TJ.