12 WRITINGS OP JAMES SMITHSON. 



diminution of size, and the saline beads on cooling assumed 

 their usual opacity. 



(D) A bit of Tabasheer was laid on a plate of silver, and 

 a little litharge was put over it, and then melted with the 

 blow-pipe. It immediately acted on the Tabasheer, and 

 covered it with a white glassy glazing. By the addition of 

 more litharge the mass was brought to a round bead; though 

 with considerable difficulty. This bead bore melting on the 

 charcoal, without any reduction of the lead, but could not 

 be obtained transparent. 



(E) The ease with which this substance had melted with 

 vegetable ashes, led to the trial of it with pure calcareous 

 earth. A fragment of Tabasheer, fixed to the end of a bit 

 of glass, was rubbed over with some powdered whiting. As 

 soon as exposed to the flame of the blow-pipe, it melted 

 with considerable effervescence ; but could not, even on the 

 charcoal, and with the addition of more whiting, be brought 

 to a transparent state, or reduced into a round bead. 



Equal weights of Tabasheer and pure calcareous spar, 

 both reduced to fine powder, were irregularly mixed, and 

 exposed in the platina crucible to a strong fire in a forge for 

 20' ; but did not even concrete together. 



(F) When magnesia was used, no fusion took place at the 

 blow-pipe. 



(Q) Equal parts of Tabasheer, whiting, and earth of 

 alum precipitated by mild volatile alkali, were mixed in a 

 state of powder, and submitted in the platina crucible to a 

 . strong tire for 20', but were afterwards found unmelted. 



Examination of the other specimens. 

 No. I. 



This parcel contained particles of three kinds; some 

 white, of a smooth texture, much resembling the foregoing 

 sort; others of the same appearance, but yellowish; and 

 others greatly similar to bits of dried mould. 



The white and yellowish pieces were so soft as to be very 



