225 



mixed with it. It is very difficult to determine when this 

 substance can be considered anhydrous. Prepared by eva- 

 poration over sulphuric acid in vacuo, it is quite dry, and 

 may be powdered, but if heated it liquefies below 212°, and 

 continues giving out watery vapour until the temperature is 

 raised to 350°, beyond which the organic matter itself cannot 

 be heated without decomposition. On cooling it reassumes 

 its perfectly dry aspect, and may be easily powdered. 



It was hence analyzed in all these stages of desiccation, 

 with the following results. It contained : 



Dried in vacuo. 



Carbon .... 34.74 

 Hydrogen . . . 6.93 

 Oxygen .... 58.33 



100.00 



H27 

 0,9 



Formula deduced. 



zz 138 34.78 

 = 27 6.80 



= 232 58.42 



397 100.00 



Dried at 212". 



Carbon . . 49.97 51.20 

 Hydrogen . 5.18 5.28 

 Oxygen . 44.85 43.52 



100.00 100.00 



Dried in an oil bath at 320", 



Carbon .... 52.55 

 Hydrogen . . . 5.15 

 Oxygen .... 42.30 



Formula deduced. 



100.00 



^23 

 Hi3 



0,r, 



C23 



H]2 

 Ou 



138 

 13 



120 



50.92 



4.80 



44.28 



271 100.00 



Formula deduced. 



138 



12 



112 



52,67 



4.58 



42.75 



262 100.00 



By adding a solution of xanthorhamnine to solutions of 



acetate of lead, two combinations may be formed, one by 



neutral acetate of lead, the other by using the tribasic salt. 



But it is difficult to obtain either unmixed with some traces 



of the other, and thence the analysis of both vary a little 



from the true atomic constitution. Thus the tribasic salt 



gives 



t2 



