| RefNo | MM/4/84 | 
| Level | Item | 
| Title | Letter from Henry Cavendish, William Watson, Benjamin Franklin and J Robertson, to the Royal Society | 
| Date | 18 November 1773 | 
| Description | On having viewed the lightning conductors fixed on the wall of the Powder Magazines at Purfleet, and judging them to be agreeably constructed | 
| Extent | 1 side | 
| Format | Manuscript | 
| AccessStatus | Open | 
Fellows associated with this archive
| Code | PersonName | Dates | 
| NA7974 | Franklin; Benjamin (1706 - 1790) | 1706 - 1790 | 
| NA7588 | Watson; Sir; William (1715 - 1787) | 1715 - 1787 | 
| NA8163 | Cavendish; Henry (1731 - 1810); natural philosopher | 1731 - 1810 |