426 Olservations, &c. on the Papyri 
dance of ammonia by distillation, and left ashes Se ee much 
phosphate of lime. 
3dly. An Account of the Experiments on Papyri made in the 
Museum at Naples. 
Only one method, and that a very simple mechanical one, has. 
been adopted for unrolling the MSS. It was invented by Padre 
Piaggi, a Roman, and consists in attaching thin animal mem- 
brane bya solution of glue to the back of the “MSS. and carefully 
elevating the layers by silk threads when the glue is dry. 
In considering this method in its general application, some 
circumstances occurred to me which afforded an immediate im- 
provement. A liquid solution of glue had been used, which, 
when the texture of the MSS. was loose or broken, penetrated 
through three or four layers, and these, when the glue dried, 
separated together. ‘To obviate this objection, I mixed the so- 
lution of glue with a sufficient quantity of alcohol to gelatinize 
it; and a mixture of the jelly and the fluid being made and ap- 
plied by a camel’s hair brush, a film of jelly remained on the ex- 
terior of the surface of the leaf, which attached itself to the 
membrane, j 
The effect of the solution of glue applied in the ancient me- 
thod, was always likewise to separate the layers, by expanding 
the imperfectly carbonized fibres. In the improvement I have 
mentioned, the alcohol, from its greater lightness, penetrated 
further into the papyrus, but produced its greatest effect imme- 
diately on the first layers. 
I adopted in some cases ether, as an agent for assisting the 
separation of the layers; and it was always found very efficacious, 
whether it was necessary to remove a single layer, or several 
layers at a time, in order to discover if a roll contained charac- 
ters. The ether was applied by a camel’s hair brush lightly to _ 
the surface of the leaf, when its operation was intended to be 
merely on that leaf; and it was suffered to sink deeper accord- 
ing 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. | employed sulphuric 
ether, and for the brown ones muriatic or nitric ether in their 
impure states, 7. e. mixed with much alcohol. 
No artificial modes had been employ ed by the Neapolitans for 
drying the papyrus in the operation of attaching the membrane, 
and no means, except mechanical ones, of detaching it after it 
was dried. 
By throwing a stream of air gradually warmed till it attained 
a temperature about that of boiling water upon the surface of 
the. 
