hickness, the floor
joists were seldom on a straight line, and measurements made at similar
places, e.g., the two ends of a room, seldom agree.

[Illustration: Pl. LV: West Front of Casa Grande Ruin.]

A series of precise measurements gives the following results: Outside
eastern wall, at level 3 feet above center of depressed area adjoining
the ruin on the east, 59 feet; western wall at same level, 59 feet 1
inch; northern and southern walls, at same level, 42 and 43 feet
respectively. These measurements are between points formed by the
intersection of the wall lines; the northeastern and southeastern
corners having fallen, the actual length of standing wall is less. At
the level stated the northern wall measures but 34 feet 4 inches, and
the southern wall 36 feet 10 inches. A similar irregularity is found in
the interior measurements of rooms. The middle room is marked by an
exceptional departure from regularity in shape and dimensions. Both the
east and west walls are bowed eastward, making the western wall convex
and the eastern wall concave in reference to the room.

Precise measurements of the middle room at the second floor level, 8
feet above the base previously stated, are as follows: Eastern side, 24
feet 81/2 inches; western side, 24 feet 2 inches; northern side, 9 feet 31/2
inches; southern side, 9 feet 1 inch. The eastern room is a little more
regular, but there is a difference of 11 inches between the measurements
of the northern and southern ends. A similar difference is found in the
western room, amounting there to 6 inches. The northern and southern
rooms do not afford as good bases for comparison, as a corner is missing
in each; but measurements to a point where the interior wall surfaces
would intersect if prolonged, show variations of from 6 inches to a
foot. The statement that the ruin exhibits exceptional skill in
construction on the part of the builders, is not, therefore, supported
by facts.

_Detailed Description._

The Casa Grande ruin is often referred to as an adobe structure. Adobe
construction, if we limit the word to its proper meaning, consists of
the use of molded brick, dried in the sun but not baked. Adobe, as thus
defined, is very largely used throughout the southwest, more than nine
out of ten houses erected by the Mexican population and many of those
erected by the Pueblo Indians being so constructed; but, in the
experience of the writer, it is never found in the older ruins,