146 



Dr. Stenhouse on Rubia munjista. 



[1864, 



munjistine sublimes in golden scales and broad flat needles of great beauty ; 

 these have all the physical characters and the same composition as the 

 original substance. If the sublimation be continued for a long time at the 

 lowest possible temperature consistent with its volatiHzation, the whole of 

 it is obtained with scarcely any loss. 



The following are the results of the ultimate analysis of different samples 

 of munjistine : — 



I. -314 grm. of munjistine yielded '732 grm. carbonic acid and '106 grm. 

 of water. 



II. '228 grm. of munjistine yielded '535 grm. carbonic acid and '0765 

 grm. water. 



III» '332 grm. of munjistine yielded '7795 grm. of carbonic acid and 

 •1125 grm. of water. 



IV. '313 grm. of munjistine yielded "734 grm. of carbonic acid and 

 •1095 grm. of water. 



Theory. I. II. III. IV. 



C,6=96 64-00 63-60 64-00 64-04 63-97 

 6 4-00 3-77 3-73 3*76 3-89 



0^=48 32-00 32-63 32-27 32-20 32-14 

 The carbon in No. I. is rather lower than that of the other three ; this is 

 owing to the specimen not being quite free from alumina j moreover it was 

 burnt with oxide of copper, the others with chromate of lead. No. III. is 

 the sublimed munjistine. All the analyses were made on specimens pre- 

 pared at different times. 



Lead Compound. 



When aqueous or alcoholic solutions of munjistine and acetate of lead 

 are mixed, a flocculent precipitate of a deep orange- colour falls, which 

 changes to scarlet on the addition of a shght excess of acetate. The best 

 method of preparing it is to dissolve munjistine in hot spirit and add to 

 the filtered solution a quantity of acetate of lead insufiicient to precipitate 

 the whole of the munjistine, then to wash thoroughly with spirit, in which 

 the lead compound is but slightly soluble, and dry first in vacuOj and then 

 in the water-bath. 



I. -836 grm. lead compound gave -407 grm. oxide of lead. 



II. -625 grm. lead compound gave -302 grm. oxide of lead. 



III. -428 grm. lead compound gave -2075 grm. oxide of lead. 



IV. -523 grm. lead compound gave '253 grm. oxide of lead. 



V. -2705 grm. lead compound gave -3445 grm. of carbonic acid and 

 •0445 grm. water. 



VI. '5350 grm. lead compound gave '6830 grm. carbonic acid and '0920 

 grm. water. 



Theory. I. II. III. IV. V. VI. 



=486 34-93 34-73 34-82 



= 25 1-82 1-83 1-91 



Ol. =200 14-55 



. 6PbO 669-6 48-70 48-70 48*32 48-50 48-38 



