Annoyingly, Davy doesn’t give a lot of information about the furnace:
‘During a stay that I made at Florence in the end of March and beginning of April, I made several experiments on the combustion of the diamond, and of plumbago [graphite], by means of the great lens in the Cabinet of Natural History; the same instrument as that employed in the first trials on the action of the solar heat on the diamond, instituted by Cosmo III…’
