422 
Proceedings of the Royal Society 
The inquiry, which I propose to enter upon this evening, appears 
to me to be interesting in itself, and also to possess some importance 
in its relation to at least one problem connected with the general 
study of historic evidence. I am very sensible of the honour 
conferred by the Council of the Royal Society in inviting me to lay 
the case before you, and also of its courtesy in according me such 
ample time for its statement. Allow me to express the hope that 
this generous confidence may not prove to have been misplaced. 
A large part of my paper must be occupied with questions on 
which there is fair room for considerable difference of opinion. On 
these points, while offering my own view, I am very far from wishing 
to dogmatise. On the contrary, I not only expect, but I desire to 
be listened to in a free and critical spirit ; and I trust that I shall 
not be found to encounter opposing theories in the spirit of that 
disputant who is reported to have said, “ I am perfectly open to 
conviction, but show me the man who can convince me.” 
Before diverging into paths confessedly obscure, it is necessary to 
take our stand for a moment upon ground which is recognised as 
firm and clear. Accordingly, I start from the enunciation of a 
statement, for which I may fairly claim a general and undisputed 
acceptance. It is this : — 
“ The cities of Pompeii and of Herculaneum were overwhelmed 
by masses of volcanic matter poured forth from Mount Vesuvius 
in an eruption, which took place in a.d. 79.” 
The evidence on which this assertion now rests does not require 
any detailed examination. I am probably by no means the only 
person here present who has enjoyed the good fortune of visiting 
the remarkable ruins of these cities. In our days of cheap and 
rapid locomotion, it is in the power of numbers to travel to the sunny 
land and to gaze upon these disinterred remains. A comparison of 
the information thus obtained with that derived from the records 
of antiquity amounts to a virtual demonstration. Those who prefer 
the less troublesome, but less direct proof gained by study, may find 
ample accounts of the matter in any good Encyclopedia, or in hand- 
books for travellers to Southern Italy, A more lavish expenditure 
will enable them to purchase volumes richly illustrated with pictures 
of the works of art discovered in the buried cities. The arguments 
of Signor Lippi in 1816, to the effect that water without any igneous 
