129
PRESIDENTIAL ADDRESS
Concerning the Age of Things
BY LAURENCE S. HARLEY, B.Sc, M.I.E.E.
[Delivered 28 March, 1958]
AT THE risk of appearing pedantic, I want you to be
quite clear what are the Tilings I propose to consider
and, indeed, also what I mean by Age. The Things I shall
talk about are things of long ago, once living perhaps, but
now long buried and chosen for study by men interested in
antiquity. I shall not consider things now living, or recently
formed.
The Age of these things with which we are concerned
is the time interval from the present back to the distant
past when they first came to be what they are. But this
is still loose thinking: in the case of a flint arrowhead. I
suppose it is clear that we are interested in knowing when
it was made and used by Man, not when the flint itself was
formed by redeposition of silica in the chalk.
Nevertheless, there are difficult borderline cases when it
is desirable to specify exactly which time-interval we mean
by "age"; for example, in the case of a piece of timber
found in the side of a Roman well, we may want to know
the time when the tree was felled to make a battering-ram
for the Claudian invasion, or when it was taken 200 years
later from the house in which it had been built in the
meantime, to be split and used in a third-century well.
Having started by complicating the subject, I will now
simplify it again by saying that in every case what we seek
is a clock of some kind. Until fairly recently, an external
clock had to be provided by the general accumulation of
evidence as to the number of years which have elapsed since
certain landmarks occurred in history and pre-history.