Eh| 6| | 3 20 ECONOMY OF Caxro I.(un! Ä, So to the ſacred Sun in MEMSXON 8 fane, w. nv Spontancous concords quired the matin ſtrain; Them 6 iw | light being abforbed and again emitted from bodies when they||. wäh are removed into darkneß. But Beccari further pretended, that| ome calcareous compoſitions when expoſed to red, EE or| Nov blue 10781 through coloured glaſſes, would on their being| brought into a DEE room emit coloured lights. This miſtaken Much fact of Beccari's,- Mr. Wilſon decidedly refutes; and among inen many other curious experiments diſcovered, that if oyſter-ſhells were thrown into a common fire and calcined for about half an Ad hour, and then brought to a perſon who had previouſly been| Wan ſome minutes in 2 dark room, that many of them would ex-| hibit beautifal iniſes of priſmatic colours, whence probably aroſe| Gugr Beccari's miſtake. Mr. Wilſon hence contends, that theſe kinds| of phoſphori do not emit the light they had previouſly received,. but that they are ſet on fire by the ſun's rays, and continue for 0, ſome time a flow combuſtion after they are withdrawn from the Ee light. Wilſon's Experiments on Pt TOPE Dodfſley, 1775.| E3 en The Bolognian flone is a ſelenite, or gypſum, and has been| FE Jong celebrated for its phoſphoreſcent quality after having been| NEN burnt in a ſulphurous fre; and expoſed when cold to the ſun's M light. It may be thus well imitated; Calcine oyſter-ſhells half M an hour, pulverize them when cold, and add one third part of flowers of ſulphur, preſs them cloſe into a ſmall crucible, and calcine them for an hour or longer, and keep the powder in a NN phial cloſe ſtopped. A part of this powder is to be expoſed for a N u. minute or two to the ſunbeams, and then brought into a aark"7 room. JThe calcined Bolognian ſtone becomes a calcareous Ni hepar of ſulphur; but the calcined ſhells, as they contain the 4 0. animal acid, may alfo contain ſome of the phoſphorus of Kun-!"vl" kel. See additional notes, No. 3! Tn Memnonr's fane. 1. 183. Sce additional notes, No. VIII.| | '| | a“[ e<emummme EEE Ei. GEIGE R 1921 2558502 EL BELEGEN: EEE