Vol. 7, 1921 
PHYSICS: C. BARUS 
71 
descent from the Basket-maker is indicated by the dolicocephalic bead 
form and absence of cranial deformation ; by the elaborateness of the sandal 
weaves; the presence of a degenerate type of twined- woven bag; and by 
the use of fur cloth instead of feather cloth. The absence of cotton from 
both cultures should be noted. Advances over the Basket-maker are 
seen in the appearance of pottery (albeit of a crude type), in the pres- 
ence of permanent house-structures, and in the elaboration of the carry- 
ing straps. 
The third culture is the one which we formerly called the Slab-house. 
As that term, based on a feature of the architecture, is equally applicable 
to the Post- Basket-maker we have discarded it and substitute the name 
Pre-Pueblo. This group is allied to the preceding one most closely ap- 
parently in house-types, and in the possession of pottery, though its 
characteristic wares are much the more highly developed of the two; 
it differs sharply from the Post-Basket-maker in the practice of skull 
deformation, in the possession of cotton, turkey-feather cloth and twilled 
basketry. Traits that it shares with the succeeding culture, the Cliff- 
dweller-Pueblo, are: skull deformation; decorated pottery ; cotton ; turkey- 
feather cloth; the bow. 
From the above data it seems probable that the Basket-makers were 
the direct ancestors, both physically and culturally, of the Post-Basket- 
makers; the latter, however, had made considerable advances (houses, 
pottery). A direct line of descent from Post-Basket-maker to the Pre- 
Pueblo might be inferred from the similarity in house-types; but the 
Pre-Pueblo are in most respects much more nearly allied to their successors, 
the Cliff-dweller-Pueblo people, than they are to the earlier group. 
To sum up: Basket-maker is probably ancestral to Post-Basket-maker; 
Pre-Pueblo to Cliff-dweller-Pueblo; the genetic relationship of Post-Basket- 
maker to Pre-Pueblo may be inferred, but is still doubtful. A more de- 
tailed knowledge of the material cultures of the two middle groups is 
necessary, as well as studies to determine whether or not skull deformation 
alone is capable of producing the marked appearance of brachycephaly 
exhibited by the crania of the two later groups. 
THE OPEN MERCURY MANOMETER READ BY DISPLACEMENT 
INTERFEROMETRY 1 
By Carl Barus 
Department of Physics, Brown University 
Communicated February 2, 1921 
1. Apparatus. — This is practically a U-tube, AmA' , figure 1, with wide 
shanks, AA' } connected by a channel, m, below. A and A' are cylindrical 
hollows, 2-3 cm. deep and about 5 cm. in diameter, cut in a rectangular 
1 Advance note from a report to the Carnegie Inst, of Washington, D. C. 
