53 
It is to a great extent soluble in benzole, ether, absolute 
alcohol, &c., leaving behind a blackish grey residue in which 
gum was found. 
Lacquer on exposure to the atmosphere rapidly loses its 
weight and at the same time blackens on its surface ; although 
this loss is different in different specimens, yet on the average 
of those which I have examined it seems to vary from 25 
to 37 per cent. 
When the lacquer is exposed to the action of sunlight in 
hermetically sealed vessels in the atmosphere or in carbonic 
acid, blackening does not take place, but a large quantity of 
moisture collects on the sides of the vessel. 
The loss of weight in the atmosphere is almost if not en- 
tirely due to the escape of water, with a minute quantity of 
carbonic acid which may be formed by the oxidation of 
some organic compound existing in the lacquer. The attempt 
has been made to estimate the relative amounts of carbonic 
acid and water, yet it was not successful at the time, being 
too difficult, and it must be left open to some future inves- 
tigation. 
It is by many supposed to be due to the combined action 
of light and air that the blackening of lacquer in the air 
takes place ; but this seems to be erroneous from the follow- 
ing experiments. First, I made a square box which had a 
well fitting sliding door and the inside of which was made 
perfectly black, so that practically no light is admitted to 
enter. In it was placed a small quantity of lacquer at dark 
and the door closely shut ; on looking at it the next morn- 
ing it was observed that the lacquer had turned perfectly 
black, proving that it is not the light that blackens the 
lacquer. 
Second, the bottle in which I kept my lacquer for more 
than three months during my examination was exposed to 
the incident light of the laboratory; the surface of the 
lacquer was turned perfectly black, forming a wall as it 
