INVESTIGATION OF JAPANESE LAQUOK. 257 



due to the oxygeu of the air, but not to the light aloue uor 

 to the coinbiued action of air aud light (as might have beeu 

 supposed) . 



The laquor when distilled with water gives a colourless 

 distillate which is slightly acid to test-paper. The attempt 

 has been undertaken to examine this acid, but not success- 

 fully, on account of too minute a quantity of the acid that 

 is evolved. 



The distillation by itself and in a current of steam Avere 

 tried ; but the results in both cases were the same as the 

 first one. Then, lastly, distilled with a small quantity of 

 dilute HjSO^. into the solution of acetate of lead; but 

 scarcely any precipitate was obtained. 



The laquor mixes with any kind of fixed oil in all pro- 

 portions ; hence the oil is often added as an adulteration ; 

 but sometimes a very small quantity is added purposely to 

 make the laquor more mobile. 



The specimen of urushi which I obtained in my labora- 

 tory for examination consisted of the following three sub- 

 stances : — 



I. II. 



Part soluble in absolute alcohol 5824 S^'^S 



Gum 6-34 6-30 



Residue 2*24 2*30 



Moisture and other volatile maUer 33"i8 33*i7 



I00"0 lOO'O 



As I have mentioned already, the laquor loses its weight 

 rapidly when exposed to the atmosphere : for the determi- 

 nation I weighed out samples each time from a well-stop- 

 pered bottle and determined by difference. 



Then this was treated with absolute alcohol, and the 

 filtrate evaporated to small bulk, and dried at ioo° C. until 

 the weight remains constant. This is put down as " part 

 soluble in absolute alcohol " in the above analysis. 



SER. III. VOL. VII. s 



