•534 Experiment on the Tufiori 



eter. The protuberance, as well as the contiguous 

 portion of lime, was converted into a perfectly white 

 and glistening enamel ; a magnifying glafs difcovered 

 a few minute pores, but not the llighteft earthy ap- 

 pearance. This experiment was repeated feveral 

 times, and with uniform fuccefs ; may not lime there- 

 fore be added to the lift of fufible bodies ? 



Magnesia. — The fame circumftances that rendered th^ 

 operating upon lime difficult, exifted, in a ftill great- 

 er degree, with refpect to magnelia ; itslightnefs and 

 pulverulent form rendered it impoffible to confine it 

 for a moment upon the charcoal, and as it has very 

 little cohelion, it could not be (haped by the knife as 

 the lime had been. After being calcined, at full ig- 

 nition, in a covered platinum crucible, it was knead- 

 ed with water, 'till it became of the eonliftence of 

 dough. It was then ftiaped into a rude cone as acute 

 as might be, but ftill very blunt ; the cone was three 

 fourths of an inch long, and was supported upon a 

 coiled wire. 



The magnelia, thus prepared, was expofed to the 

 compound flame : the efcape of the water caufed the 

 vertex of the cone to fly off in repeated flakes, and 

 the top of the fruftrum, that thus remained gave 

 nearly as powerful a reflection of light as the lime 

 had done ; from the bulk of the piece (it being now 

 one fourth of an inch in diameter at the part where 

 the flame was applied) no perceptible finking could be 

 expeded. After a few feconds, the piece being ex- 

 amined, with a magnifying glafs, no roughneffes or 

 earthy particles could be perceived on the fpot, but 

 a number of glafly, fmooth protuberances, whofe 

 furface was a perfectly white enamel; this experi- 

 ment was repeated with the fame fuccefs. May not 

 magnefia, then, be alfo added to the table of fufible 

 bodies ? 



Yttria — was the only remaining primitive earth, 

 but no fpecimen of it could be obtained. 



