16 WRITINGS OF JAMES SMITHSON. 



tate, and remained perfectly unaffected for two days ; but on 

 the third it was converted into a firm jelly like that IX. 

 (F). 



As gypsum is found to melt per se at the blow-pipe, though 

 refractory to the strongest heat that can be made in a fur- 

 nace, it was thought that possibly siliceous and calcareous 

 earths might flux together by this means, though they resist 

 the utmost power of common fires ; but experiment showed 

 that in this respect quartz did not agree with Tabasheer. 

 But this difference seems much too likely to depend on the 

 admixture of a little foreign matter in the latter body, to 

 admit of its being made the grounds for considering it as a 

 new substance, in opposition to so many more material 

 points in which it agrees with silex. 



Nor can much weight be laid on the inferior specific grav- 

 ity of a body so very porous. The infusibility of the mix- 

 ture XIII. (G) depended also, probably, either on an 

 inaccuracy in the proportions of the earths to each other, or 

 on a deficiency of heat. 



. 3. Of the three bamboos which were not split before the 

 Royal Society, I have opened two. The Tabasheer found 

 in them agreed entirely in its properties with that of No. I. 

 and II. 



It was observed that all the Tabasheer in the same joint 

 was exactly of the same appearance. In one joint it was all 

 similar to the yellowish sort No. I. In another joint of the 

 same bamboo, it resembled the variety (c) of No. II. Prob- 

 ably, therefore, the parcels from Dr. RUSSELL, containing 

 each several varieties of this substance, arose from the pro- 

 duce of many joints having been mixed together. 



4. The ashes, obtained by burning the bamboo, boiled in 

 marine acid, left a very large quantity of a whitish insolu- 

 ble powder, which, fused at the blow-pipe with soda, effer- 

 vesced and formed a transparent glass. Only the middle 

 part of the joints was burned, the knots were sawed off, 

 lest being porous, Tabasheer might be mechanically lodged 

 in them. However, the great quantity of this remaining 



