ILLUSTRATIONS. 
—_— 
PLATES. 
PAGE. 
Prats 1. 
_ A. Bottomless pits near Flagstaff, illus- 
trating drainage through lime- 
BtONE....cccceereresececreceses 
PuaTeE 2. 
Cross-identification of rings of growth 
in yellow pine (Pinus ponderosa) . 
Puate 3. 
‘A. Section of Scotch pine from Southern 
England.........sss0eseverees 
B. Section of Scotch pine from coast of 
Puarte 4. : 
A. Section of Scotch pine from Os, Nor- 
Prats 5. 
A. Upland contours, above Camp 6 in 
Sequoia Grove: D-19.........- 
B. Basin contours, Indian Basin, look- 
ing 8. E.: D-12 and 13 in center. 
Puiate 6. 
A. Cutting radial sample from end of 
log, Converse Hoist, D-20, age 
2800 years.....--seeerecereres 
B. Site of oldest tree, Converse Hoist, 
D-21, age 3200 years. ........- 
Prats 7. 
A. Cutting sample from stump, Enter- 
prise: D-22, age 3000 years..... 
_ B. Centennial stump, Enterprise; cut in 
1874, D-23, age 3075 years..... 
Puate 8. 
A. Section of Scotch pine from Ebers- 
walde, Prussia, showing solar 
B. Another section from the same forest, 
showing same rhythm.......... 
Pate 9. 
A. Periodogram of the sunspot numbers, 
1755-1911. Corrugations show 
periods. The numbers give length 
of period in years. The white 
line is the year 1830 and shows 
DRAKE. ccc dcasccescsssoscesies 
12 
12 
52 
74 
74 
PAGE, 
Piate 9—continued. 
B. Differential pattern used in making 
the periodogram, consisting of 
the sunspot curve mounted in 
multiple..........0eeeeceerees 88 
C. Same pattern photographed out of 
focus to show discontinuities in 
the vertical lines..........+++++ 88 
D. Sweep of sunspot numbers, 1755-1911 88 
EB. Differential pattern of sunspot num- 
bers made by the periodograph 
PTOCESS..... eee eee eee e eee eee 88 
PuaTeE 10. 
‘A. The automatic optical periodograph. 94 
B. Differential patterns of Sequoia rec- 
ord, 3200 years at 11.4......--- 94 
Puate 11. 
A. Periodogram of standard 5-year 
PCTIOd........-2-ecceeeesececee 96 
B. Periodogram of mixed periods...... 96 
C. Periodogram of sunspot numbers 
1610-1910... .. cc ee eee eee ee ene 96 
D. Periodogram of Flagstaff 500-year 
record to show cycles between 
4 and 15 years of length......-- 96 
E. Periodogram of same continued to 
QB YOATS...ccceeeecceeneceeere 96 
Pate 12. Differential patterns: 
a. Sunspot numbers, 1610-1910 at 11.4. 108 
b. 57 European trees, 1830-1910 at 11.4. 108 
c. 80 European trees, 1800-1910 at 11.4. 108 
d. South Sweden, 1830-1910 at 12.0... 108 
e. Vermont group, 1650-1910, at 11.3. 108 
f. Flagstaff group, 500 years, at 11.4... 108 
g. Flagstaff group at 23.5 years......-. 108 
h. Norway, 1740-1910, at 23.8 years... 108 
i. Austria, 1830-1910, at 22.0 years... 108 
j. Norway, N-2 400 years, at 33.0.... 108 
k. Vermont, 250 years, at 32.5.....--- 108 
1. Sweden, 1740-1910, at 37.0.....--- 108 
m. Sequoia, 1800-250 B. C., at 33.0.... 108 
n. Flagstaff, 500 years, at 33.0.......+ 108 
v. Sequoia, 3200 years at 101.......-- 108 
p. Flagstaff, 500 years at 190. ic WES 52 108 
q. Standard 5-year period at 5.0 years. 108 
r. 5 to 10 year logarithmic variable 
period at 8.0.......+eeeeeeeeee 108 
