and from our experience of our own mental powers.
This way of getting at it makes it really our own. We know what we mean
by it, and it is no longer a mere traditional form of words. It is the
same with everything else; nothing becomes our own by being just told
about it.

For instance, if I show an artist a picture, and he tells me that a boat
in it is half a mile away from the spectators, I may accept this on his
authority, because I suppose he knows all about it. But if next day a
friend shows me a picture of a bit of coast with a fishing-boat in the
distance, and asks me how far off that boat is, I am utterly stumped
because I do not know how the artist was able to judge the distance.
But if I understand the principle, I give my friend a very fair
approximation of the distance of the boat. I work it out like this. I
say:--the immediate foreground of the picture shows an amount of detail
which could not be seen more than twenty yards away, and the average
size of such details in nature shows that the bottom edge of the picture
must measure about ten yards across. Then from experience I know that
the average length of craft of the particular rigging in the picture is,
say, about eighty feet, and I then measure that this length goes sixteen
and a half times across the picture on the level where the boat is
situated, and so I know that a line across the picture at this level
measures 80 x 16-1/2 = 1320 ft. = 440 yards. Then I make the
calculation: 10 yds.: 440 yds.:: 20 yds.: the distance required to be
ascertained 440 x 20 / 10 = 880 yds. 1760 yds. = 1 mile and 1760 / 2 =
880 yds. Therefore I know that the boat in the picture is represented as
being about half a mile from the spectator. I really know the distance
and do not merely guess it, and I know _how_ I know it. I know it simply
from the geometrical principle that with a given angle at the apex of a
triangle the length of a perpendicular dropped from the apex to the base
of the triangle will always bear the same ratio to the length of the
base, whatever the size of the triangle may be. In this way I know the
distance of the boat in the picture by combining mathematics and my own
observation of facts--once again to co-operation of Law and Personality.
Now a familiar instance like this shows the difference between being
told a thing and really knowing it, and it is by an analogous method
that we have now arrived at the conclusion that the Perfect Word is a
combina