UK, 1807

Wollaston purchased two platina thermometers from Chas. Malacrida of High Holborn St. for 19s.

Wollaston assumed Johnson purchased 1 Libra for S$ 6. silver; at 1807 forex on New Dollars:

1806: 1 Troy Ounce platina (Importer's Cost, 76.3% ore)  = £ 0.0886 - 0.1063
1806: 1 Troy Oz Pt (Importer's Cost, .999)  = £ 0.1162 - 0.1394
1806: 1 Troy Oz Pt (Wollaston's Labor, Per Ozt)  = £ 0.10
1806: 1 Troy Oz Platinum (Lowest Cost Basis, .999)  = £ 0.2162 - 0.2394