of Edinburgh, Session 1884 - 85 . 
187 
6. The juice heated to 60°~63° C., sample did not dry. 
7. „ „ 80° C., „ ,, 
8. „ „ 100° C, 
Mr J. Takayama, working very carefully on a sample bought at 
Tokio, found the limit of activity of nitrogenous matter to be 
70°-73° C., hut with the Yoshino sample (which contains much less 
nitrogenous matter and water) he confirmed my former number of 
60° C. as the limit. His method was to place the juice in a boat in a 
tube immersed in gradually heated water. 
Next, glass plates coated with urushi juice were put under a bell 
jar containing an experimental gas, and left to dry at the tempera- 
ture of the air, ranging between 13° and 15° C. 
1. In dry air the sample did not dry. 
„ moist ,, 
„ dry oxygen 
,, moist „ 
„ dry hydrogen 
,, moist ,, 
dried after 4 hours, 
did not dry. 
dried after 2J hours. 
9. 
10 . 
„ dry nitrogen 
„ moist „ 
did not dry. 
dried imperfectly after 1J- day. 
„ dry carbonic acid the sample did not dry. 
„ moist ,, „ dried very slowly after 2 
days. 
„ did not dry. 
,, dried imperfectly after 1J 
day. 
The most legitimate inference to be drawn from all these experi- 
ments is that the combination of oxygen and moisture at the tempera- 
ture of 20° C. is an essential condition for the display of the fullest 
activity of the diastatic matter, and consequently most favourable for 
the drying of the lacquer. With either the increase or decrease of 
temperature, the drying power decreases ; at 0° to 2° C. it is 
temporarily suspended, and at from G0° to 70° C., the substance en- 
tirely loses its activity ; this is then the point at which the coagula- 
tion of the albuminoid matter takes place — or, in other words, the 
diastatic action ceases. With other gases, however, I am inclined 
to think that some atmospheric air, which may have been present in 
them, might have favoured the conditions for drying ; otherwise it 
would not have been possible. Mr J. Takayama has recently con- 
firmed the view that lacquer juice never dries in an atmosphere 
VOL. xm. 
o 
