200 
Sir Humphry Davy on the papyri 
layer, or several layers at a time, in order to discover if a 
roll contained characters. The ether was applied by a camel’s 
hair brush lightly to the surface of the leaf, when its opera- 
tion was intended to be merely on that leaf ; and it was 
suffered to sink deeper according as more layers were to be 
separated ; the mere circumstances of its evaporation, which 
in some cases I assisted by heat, tended to detach the layers. 
-For the black MSS. I employed sulphuric ether, and for the 
brown ones muriatic or nitric ether in their impure states, i. e. 
mixed with much alcohol. 
No artificial modes had been employed by the Neapolitans 
for drying the papyrus in the operation of attaching the 
membrane, and no means, except mechanical ones, of de- 
taching it after it was dried. 
By throwing a stream of air gradually warmed till it at- 
tained a temperature about that of boiling water upon the 
surface of the leaf, I succeeded not only in drying the layers 
with much greater rapidity, but likewise in separating them 
with more delicacy. 
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 ope- 
rators. 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 
