256 MR. SADAMA ISHIMATSU ON A CHEMICAL 



matter^ as water &c., to escape ; it is thus prevented from 

 drying any further. However^ in case o£ moist air, the 

 drying takes place much more slowly, so the volatile matters 

 which are contained in the interior have sufficient time to 

 escape, and the complete drying takes place. In winter 

 the laquor dries with much more difficulty than in summer 

 time; and in the ^' rainy season ^' especially it dries very 

 quickly, probably due to the dampness of the atmosphere 

 for the above reason. It is also said that '' urushi " dries 

 much quicker by the addition of a small quantity of alco- 

 hol or camphor. 



Fused with caustic potash just at the temperature at 

 which potash fuses, then treated with water and filtered, 

 on addition of a little dilute H^SO^. to neutralize the alkali 

 no precipitate was obtained. 



The blackening of the laquor in the air is by many 

 supposed to be due to the combined action of light and air ; 

 but this was proved to be erroneous. First, I made a 

 square box which has a well-fitted sliding cover, and the 

 inside of which was made perfectly black, so that no light 

 is admitted to enter ; in it a small quantity of fresh laquor 

 on a piece of paper was put in at night in the dark ; and on 

 looking the next morning it was observed that the surface 

 of the laquor was covered with a perfectly black wall, 

 proving that it is not due to the light. 



Second, the bottle in which I kept my laquor more than 

 three months during my examination was exposed to the 

 incident light of the laboratory ; then the surface of the 

 laquor in the bottle turned perfectly black, while those 

 portions which were in contact with the sides of the bottle, 

 which receives as much light as if there were not any glass 

 sides before it, was not at all blackened. 



This phenomenon is just complementary to the first one, 

 that the blacking in the atmosphere is, in all probability. 



