72 WRITINGS OF JAMES SMITHSON. 



temperature of 61 Fahr.; consequently its density is 3.750. 

 These 42 grs. of this stone by laying in the water did not 

 absorb intd their substance a quantity of it equal to one- 

 tenth of a grain. 



It does not mark glass, and is readily scraped to a powder 

 by a knife. It marked sulphate of barium. Its hardness 

 and that of fluoride of calcium appeared to be the same. 



It showed no electricity by heat. By friction it readily 

 became electrified. 



In the fire it lost no weight. 



At the blow-pipe, it readily melted. The little bead while 

 in fusion was transparent. On evolving, it became opaque. 

 The transparency of the bead in a melted state is best seen 

 with a very minute one. On fusing this matter long, it 

 spreads on the coal, and becomes a refractory mass. 



With borax, it dissolved with great effervescence into a 

 brown glass. If much stone was used, the glass appeared 

 quite black, but drawn out to a thread with the tongs, it 

 was found to be of a fine hyacinth colour. These colours 

 depend on the formation of sulphur. 



With microcosmic salt it fused with effervescence to a 

 clear colourless glass, which became opaque, and white on 

 adding more of it. 



A particle of this stone which had been fused on the 

 charcoal being laid in a drop of water on a plate of silver, 

 immediately made a black spot of sulphuret of silver on it. 



This bit of melted stone, transferred to a drop of marine 

 acid, on a piece of glass, partially dissolved with efferves- 

 cence. The solution let exhale spontaneously, afforded 

 crystals of chloride of barium. 



Some of this stone in fine powder, being heated in a drop 

 of sulphuric acid on a bit of glass, the polish of the glass 

 was destroyed. 



Water in which this stone in fine powder had been boiled 

 was not affected by solution of nitrate of lead. 



A bit of this stone, being heated in dilute marine acid, 

 emitted a few bubbles of carbonic acid, but was not other- 



