found in the ruins of Herculaneum. ' igg 
Having through the polite assistance of Sir Thomas Tyr- 
whitt procured some fragments of papyri on which Dr. 
Sickler, and some on which Dr. Hayter had operated, and 
by the kindness of Dr. Young a small portion of a MS. 
which he had himself unsuccessful!} 7, tried to unroll, I made 
some experiments upon them, by exposing them to the action 
of chlorine and the vapour of iodine, heating them gently 
after the process. These trials all afforded more or less 
hopes of success. When a fragment of a brown MS. in 
which the layers were strongly adherent, was placed in an 
atmosphere of chlorine, there was an immediate action, the 
papyrus smoked and became yellow, and the letters appeared 
much more distinct ; and by the application of heat the layers 
separated from each other, giving off fumes of muriatic acid. 
The vapour of iodine had a less distinct action, but still a 
sensible one ; and it was found that by applying heat alone 
to a fragment in a close vessel filled with carbonic acid or 
the vapour of ether, so as to raise the heat very gradually, 
and as gradually to lower it, there was a marked improve- 
ment in its texture, and it was much more easily unrolled. 
Even in these preliminary trials, I found that it was neces- 
sary to employ only a limited and small quantity of chlorine, 
too large a quantity injuring the texture of the layer, and 
decomposing the earths which it contained ; and that the 
action of heat was much more efficacious when the MS. had 
previously been exposed to chlorine, as the muriatic acid 
vapour formed greatly assisted the separation of the leaves, 
and a smaller degree of heat was required. But in all the 
trials, I found the success absolutely depended upon the 
manner in which the temperature was regulated. When the 
