|4 FufibiYity. fixed air had been expelled by heating it to red- nefs. The heat was communicated in a forge, and never laßed above three quarters of an hour, and moß commonly but twenty or twenty-five minntes. 1 he refults and the degree of heat wil 1 be feen n the following tables. To eftimate the heat, I plared one of Mr. Wedgewood’s py- rometers in a crucible nearly of the fame fize as that whieh conrained the lubftances to be tried, and fet both at an equal diftance from the nozzle of the beliows. 7 o avoid prolixity, I fupprefs Mr. Achard’s experiments when rnade on the fame mixtures, and attended with the fame refnlts; when they are mentioned, they are marked [J1. TABbEh