We said before that
we should not have been puzzled about the
18.
diviner's answer if
he had told us that he had
learnt how to estimate
depth. Now learning to estimate may, broadly speaking,
be seen in two different relations to the act of estimating; either
as a cause of the phenomenon of estimating; or as supplying us with
a rule (a table, a chart, or some such thing) which we make
use of when we estimate.