of Edinburgh, Session 1884-85. 179 
brown mass ; at about 130° C. it ignites spontaneously m fcbe aiiy 
burning with a smoky flame, and leaving an oxide of lead. 
Another salt of this acid which I examined was an iron compound.. 
Ferric 'Chloride gives a deep black voluminous precipitate,, very 
slightly soluble in alcohol, and almost insoluble in water. Some of 
the alcoholic solution was precipitated with an insufficient amount- 
of ferric chloride in order to see whether this fractional precipitation 
gave a salt of different composition. The compound obtained 
proved to be a salt of a very acid nature. Before analysis it was 
partially dried over a water- bath, and finally in a dessieator over 
sulphuric acid. 
I. 
II. 
Mean. 
Theory requires for 
(C 14 H 15r 0 2 ) 3 Fe, 
9 (C u Hi 8 0 2 ) + 2H 2 0. 
Carbon, 
74-42 
74-40 
74-41 
74-51 
Hydrogen, . 
8-18 
813 
8-15 
8-03 
Iron, . 
2-07 
2-07 
2-07 
2-08 
Oxygen, 
15-33 
15-40 
15-37 
15-38 
100-00 
100-00 
100-00 
100-00 
Another preparation of the iron salt was made with a larger 
quantity of ferric chloride than before. The compound again proved 
to be an acid salt, but of less complexity than the first. On analysis 
it gave the following result : — 
Carbon, . 
Found. 
74-56 
Theory for (C M H 17 O p .) 3 Fe ; 
3(C 14 H 18 0 2 ) requires 
74-06 
Hydrogen, 
8-06 
7-72 
Iron, 
4-29 
4-11 
Oxygen, . 
13-09 
14-11 
100-00 
100-00 
These salts have very similar characteristics. They are light sub- 
stances of a faint peculiar odour; at 120° C. they melt to a black 
mass with some decomposition, and at a somewhat higher tempera- 
ture they ignite spontaneously, giving off dense smoke of a disagree- 
able odour. The roiro lacquer is, produced, by the formation of some 
of these iron compounds. 
Experiments have shown that to prepare a good roiro lacquer, one 
must be careful to avoid adding too much iron salt to the juice; 
