ANALYSIS OF THE CHINESE RICE-STONE. 377 



c. The liquor separated from the sulphate of lead, being Alumine. 

 mixed with ammonia, yielded 7 grain? of alumine. 



An additiou of carbonate of ammonia produced no farther 

 alteration. 



Thus 100 parts of the rice-stone gave Its component 



- Oxide of lead - - . - . - 41 parts ' 



Silex - - - - . ...39 



Alumine '-----.-7 



87 



It may fairly be presumed, that the 13 parts deficient Some saline 

 were some vitrifying principle, either borax, soda, or flux * 

 potash : but the small quantity sacrificed for this analysis 

 did not allow a repetition of experiments. 



From the results of this analysis it appears, that the pre- Its fabrication,. 

 tended stone or paste of rice is nothing but a siliceous glass 

 of lead, to which a resemblance of chalcedony is given by 

 means of alumine. But it is not necessary, to employ 

 alumine purified by art for the preparation of this glass. It 

 is even very probable, that the Chinese employ feldspar, or 

 petuntze, with the properties of which they are well ac- 

 quainted, since it is with this substance and kaolin, that 

 they make their porcelain. 



Preliminary experiments have shown me, that a substance Confirmed by 

 similar to the rice-stone may be prepared, by fusing together expenment!? ' 

 8 parts of oxide of lead, 7 of feldspar, 4 of common white 

 glass, and 1 of borax: or by employing 8 parts of oxide 

 of lead, 6 of feldspar, 3 of silex, and 3 of borax, potash, 

 or soda. 



It appears, however, that no determinate proportions of Variable in the, 

 oxide of lead are observed in the preparation of the rice- f^°f°^ on of 

 stone. Hence the specific gravity of this stone varies con- 

 siderably, so that several other stones which I tried, or 

 which have been examined by others, were near a third 

 lighter than the stone I analysed. The specific gravity of 

 one small cup resembling the former, but ornamented with 

 antique Chinese figures, I found to be 3-68 ; that of several Different spe- 

 fragments of a thin vase, 3'635 ; that of a drop for the ear, C1 c S ravities « 

 in the shape of a long pearl, and labelled " oriental 

 nephritic stone", 3-58. Crell found the specific gravity of 





