Sound in the Ruins of Herculaneum. 427 
the leaf, I succeeded not only in drying the layers with much 
greater rapidity, but likewise in separating them with more de- 
licacy. 
I tried different modes of heating the air to be thrown upon 
the papyrus, such as“passing it in a spiral metallic tube through 
_ warm water or oil by a double bellows, and from a large bladder 
_ through a straight tube having a very fine orifice, and heated by 
a copper ball surrounding the body of the tube, and exposed to 
burning charcoal; which last method, from its simplicity, I found 
the one best fitted to the Neapolitan operators. By sending the 
stream of air from a greater or smaller distance, so that it mixed 
with more or less cold air, the degree of temperature applied was 
regulated at pleasure. It was always found necessary to suffer 
a few minutes to elapse after the membrane was attached, and 
then to begin with a very slight increase of temperature ; as 
otherwise, by too sudden an application of heat, the membrane 
shrivelled before it became adherent, and the vapour suddenly 
raised destroyed its union with the papyrus ; whereas, when the 
moisture was suffered to-drain from the gelatinized glue, and the 
temperature was gradually raised, the expansion of the skin and 
the upper layer separated them perfectly from the lower layers, 
so that the unrolling was performed, as it were, by chemical 
means; and an operation, which hitherto had required some 
hours for its completion, was easily effected in from 30 to 40 
minutes, 
I tried several experiments, by substituting solution of resins 
in alcohol and of gums in water for the gelatinized solution ; 
but none of them answered so well; the resins would not adhere 
with any tenacity to the membrane, and the gums, when dried, 
had not that flexibility which is an important character in the 
glue. 
The alterations in the mode of applying and drying the mem- 
brane used to detach and preserve the leaves of MSS. capable of 
being unrolled, applied generally ; I shali now mention the plans 
1 adopted for the preparation of the MSS. for this operation. 
MSS. in different states required a treatment of a directly op- 
posite kind, which was to be modified according to circumstances, 
The pale chesnut-coloured MSS., covered partially with white 
ashes, were generally of a texture so loose, and had their layers 
‘so destroyed, that there was considerable danger of tieir falling 
into pieces by mere touching. The characters that remained in 
many of them were extremely distinct ; and when a number of 
layers were taken up at once, it appeared as if they presented 
perfect columns of writing: but the fact is, the papyrus was full 
of holes, and each line was made up of letters from several dif- 
3H? ferent 
