290 Analysu of the Hoot of 



Resin 10. 1 g 



Extractive and tan 26. J * ^ 



91.8 

 Loss 8.2 



100. 



10. The loss in the above experiments may be ascribed to 

 water, for upon drying rhubarb by long exposure to heat a little 

 above 212°, the average loss of several samples was 10 per cent. 



\\. One hundred grains of rhubarb were put into a small re- 

 tort and distilled by a heat gradually raised to redness. Water 

 at first passed off, succeeded by a yellow vapour which con- 

 densed in the neck of the retort into a thick oil, and an acid 

 liquor passed into the receiver, which blackened permuriate of 

 iron. 41 grains of charcoal remained in the retort, which were 

 reduced to powder, digested in dilute muriatic acid, washed, 

 and dried at a red heat in a close vessel : they lost in this pro- 

 cess 6.5 grains. 



12. The muriatic solution on being saturated with pure am- 

 monia let fall 2 grains of a substance having the characters of 

 phosphate of lime; this was separated by filtration, and car- 

 bonate of ammonia added to the filtered liquor gave a further 

 precipitate, which, collected and dried, was found to be 4.2 

 grains of carbonate of lime. 



13. The results then of the destructive distillation of rhubarb 

 may be stated as follows : — 



Water..,. 10. 



Empyreumatic oil, gallic acid, and 1 



water formed • J 



Charcoal 34.5 



Phosphate of Hme 2. 



Carbonate of lime 4.2 



Loss 3 



100.0 



14. To ascertain in what state the 4.2 grains of carbonate of 



