Chemistry and Physics. 63 
esting action is that of oxalic acid, which has long been known, 
and the product of which is rosolic acid. The aurin, lately isola- 
ted from rosolic acid by Dale and Schorlemmer, Baeyer supposes 
to be C,,H,,O, and to result from the oxidation of leucoaurin 
C,,H,,0,, which is thus produced: 
CO,-+(C,H,0),=C, ,H, ,0,+(H,9).. 
_(2.) a Naphthol colors. a Naphthol, heated with phthalic oxide, 
yields light yellow crystals of the anhydride of the phthalein of 
naphthol, C,,H,,0,, insoluble in potassium hydrate. Heated 
with sulphuric acid, it gives a beautiful red body, C,,H, .Ox. 
Oxalic, mellitic and pyromellitic acids act similarly on anaphtho 
i ith ph 
.{3.) Resorcin colors. Resorcin heated with phthalic oxide, 
gives the phthalein of resorcin, or fluorescein, which, precipitated 
from its potash solution by hydrochloric acid, is C,,H,,0,, bu 
recrystallized from alcohol is C,,H,.0,. Reduced by zinc-dust, 
the corresponding phthalin is obtained. Heated with sulphuric 
acid, a red body is formed, which is turned blue by alkalies, and 
which yields a second red body on reduction. It closely resem- 
bles the coloring matter of litmus. Succinic oxide gives with 
rein, the succinein of resorcin; and oxalic acid, the carbonein, 
rar sme ©, ,H,0,. 
*.) Lyrogallol colors. rogallol rogallic acid) by the 
action of phthalic oxide, se satel Orr 0., the ietadein 
of pyrogallol. Reduced, it gives gallin C,,H,,0,. Heated with 
sulphuric acid, it forms cerulein, C,,H,,0,, and this on reduc- 
tion gives cerulin, Oxalic acid and succinic oxide, as well as oil 
of bitter-almonds, acetone, etc., also afford colored compounds 
When heated with pyrogallol. 
peyaroquinone gives with phthalic oxide a red | pthatein, solu- 
© in potash with a violet color, and dyeing, like brazil-wood, 
with iron and alumina mordants. Pyrocatechin, thus treated, 
Sives a phthalein, soluble in potash with a transient oo” 
; i 
maxing Compound belongs to the sugar group or to the family of 
8etable acids. Thus hematein—the coloring matter of log- 
ma: 
: i i ] °° . . 
ch amie acids or with a derivative of crotonic acid.— Ber. Berl. 
mt. Ges, iv. 658, July, 1871. G. F. B 
