PRINCIPLES OF DESIGN 53

In architecture and interior decoration, the most helpful way
to use mechanical divisions is to find a definite length or area that
can be employed over and over again, in order to give unity to a
fa§ade or a room. Of course this length or area, which we will
call a unit of measurement, must have some relation to the dimen-
sions of the house or the room. Simple arithmetical guides are
often as effective as more complicated ones. For example, units
of measure depending upon related numbers such as 2, 4, 6; or 2, 4,
8, 16; or 2, 3, 5, 8, 13, might be used. Only a few other methods
for selecting a unit of measurement for a room are described here.
They apply also to exteriors of houses*

Method I. It is supposed that a room under consideration is
rectangular. The simplest and perhaps the most effective method
is to draw a rectangle having the same proportions as the floor.
Divide its short side and also its long side into the same number of
equal lengths, five or seven or any suitable number, as in diagram
A on page 52. Then draw connecting lines so that the rectangle
is divided into small oblongs that have exactly the same propor-
tions as the room. Draw the diagonal through one or more rec-
tangles, or mark off the length of the vertical side on the horizontal,
to get additional points and lengths if they are desired. Any
length or area appearing in the figure may be taken as a unit upon
which to base the decoration and furnishing of the room.

Diagram B shows one way of dividing the same plan into in-
teresting spaces, with some important points indicated. Many
other divisions are possible.

Diagram C is a furniture arrangement plan based on the spacing
indicated in diagram B.

Method II. By means of ordinary geometric constructions
based on the dimensions of a room, it is possible to obtain in
various ways significant lengths that may serve as units of meas-
urement for articles and spaces within the room. Let the rec-
tangle abed represent the floor of a room. Let ab' — ab. Lay off
the length of the diagonal b to V on the line ad to locate the point
V*. The lines b'b", b'd, or b"d may be used as a unit of measure-
ment anywhere in the room. The point V is an important one to
be considered in placing the furniture, but its value depends some-
what on the shape of the room, as well as on the location of the
doors and windows.