found in the Ruins of Herculaneum. 425 
lours on the walls, most of which would have been destroyed or 
altered by heat, are perfectly fresh, and where papyri have been 
found in these houses, they have appeared in the form of white 
ashes, as of burnt paper; an effect produced by the slow action 
of the air penetrating through the loose ashes, and which has 
_ been impeded or prevented in Herculaneum by the tufa, which, 
‘as it were, has hermetically sealed up the town, and prevented 
any decay, except such as occurs in the spontaneous decomposi- 
tion of vegetable substances exposed to the limited operation of 
water and air; for instance, peat and Bovey coal. 
_ The results of the action of heat upon the different specimens 
of the papyri, proved likewise, that they had never before been 
exposed to any considerable degree of temperature. 
Varions specimens of papyri were heated to dull redness in-a 
small covered crucible of platinum to which air had no access. 
Some of the chesnut and most perfect specimens lost nearly half 
their weight, and the very black ones, and those containing the 
largest quantity of white ashes, all lost more than one-third, as 
the following results, selected from a number, will show : 
No. 1. 100 parts of a pale chesnut papyrus lost. 45 parts. 
No, 2, 100 parts of a decomposed papyrus, ches- 
nut-coloured, but darker, lost .. .. 43: 
No. 3. 100 parts of a very black papyrus, lost... 42> 
No.4, 100 parts of a pale papyrus, extremely 
loose in texture and partly eonverted into 
white ashés, lost). O° 938 Pot Se 
No. 5. 100 parts of another of the same kind 
MOREE 5 Waele Jaye lam uate OP Le teh Ce ee aID 
When the whole of the carbonaceous and vegetable matter of 
the papyrus was destroyed by slow combustion, the white ashes 
remaining, which were principally carbonate of lime and lime, 
proved to be from 1-16th to 1-20th of the original weight of the 
papyrus; and in those specimens which were most dense, and 
that contained a white powder, the proportion of ashes was 
greater, and a larger quantity was insoluble in acids. 
_ Ammonia was found in the products of all the papyri that I 
_ distilled, but least in those which contained no distinct characters; - 
~ from which it is probable that it arose principally from decom- 
posed glue used in the manufacture of the ink, and which had 
been principally dissolved and carried off in those papyri which 
had been most exposed to the action of water. 
 Lascertained, that what the Neapolitans called varnish, was 
decomposed skin, that had been used to infold some of the pa- 
pyri, and which by chemical changes had produced a brilliant 
animal carbonaceous substance; this substance afforded abun- 
Vol. 58. No, 284, Dec, 1821. 3H dance 
4l: 
