NOTE ON SANTONIN OR SANTONIC ACID 211 
aeid, it appears, beyond doubt, to be a stronger oxi- 
dising agent than hyponitric acid, if it could only exist by 
itself. 
Chemist, from Jlnnalen der Physik und Chemie. 
ART. LIX.— NOTE ON SANTONIN OR SANTONIC ACID. 
By H. Gualtier De Claubry. 
Being at Venice a short time ago, Professor Zantedeschi 
communicated to me the results of a curious experiment 
which he made on santonine, and which was opposed to 
those which different chemists have obtained, with several 
organic colouring matters, and in particular those of Pro- 
fessor Bizio on the purple of the ancients. 
It is known that indigo and orcine, for example, are 
colourless, and take the brilliant tint which characterises 
ihem only by the absorption of oxygen ; other analogous 
facts appear to lead to the general result that many colour- 
ing matters present the same character. 
It is known that santonin, exposed to the action of the 
solar light, speedily acquires a yellow colour ; but is oxygen 
in this case the principle which actuates this change ? Ac- 
cording to the experiments of Professor Zantedeschi, this 
does not appear to be the case. If santonin be exposed to 
isolation in the barometric vacuum, it acquires a yellow tint 
almost as bright, and nearly in the same time, although 
rather less rapidly, as another portion of the same substance, 
placed under the same luminous influence in the air or in 
oxygen. Professor Zantedeschi concludes from this that 
the colouration is due to a peculiar action of light. 
