4 WRITINGS OF JAMES SMITH80N. 



and of dried red cabbage, but produced not the least change 

 in any one of them. 



At the Jire. 



§ TV. (A) A piece of this Tabasheer, thrown into a red 

 hot crucible, did not burn or grow black. Kept red hot for 

 some time, it underwent no visible change ; but when cold, 

 it was harder, and had entirely lost its taste. Put into water 

 it grew transparent, just as it would have done, had it not 

 been ignited. 



(B) 6.4 gr. of this substance, made red hot in a crucible^, 

 were found, upon being weighed as soon as cold, to have 

 lost two-tenths of a grain. This loss appears to have arisen 

 merely from the expulsion of interposed moisture; for these 

 heated pieces, on being exposed to the air for some days,^ 

 recovered exactly their former weight. 



(C) A bit of this substance was put into an earthen cru- 

 cible, surrounded with sand, and kept red hot for some time; 

 when cold, it was still white both exteriorly and interiorly. 



(D) Thrown into some melted red hot nitre, this substance 

 did not produce any deflagration, or seem to suffer any alter- 

 ation. 



(E) A bit exposed on charcoal to the flame of the blow- 

 pipe did not decrepitate or change colour; when first heated 

 it diffused a pleasant smell ; then contracted very consider- 

 ably in bulk, and became transparent ; but on continuing 

 the heat it again grew white and opaque, but seemed not to 

 shew any inclination to melt per se. Possibly, however, it 

 may suffer such a semi-fusion, or softening of the whole 

 mass, as takes place in clay when exposed to an intense 

 heat; for when the bit used happened to have cracks, it 

 separated during its contraction, at these cracks, and the 

 parts receded from each other without falling asunder. 



If, while the bit of Tabasheer was exposed to the flame, 

 any of the ashes of the coal fell upon it, it instantly melted, 

 and small very fluid bubbles were produced. That the 

 opacity which this substance acquires on continuing to heat 



