Deep-Sea Expedition— PETTERSSON 
237 
echoes from transition layers below the surface 
of the sediment. 
Steering south from the Mindanao Deep we 
finally reached the idyllic harbor of Ternate 
on January 26, 5 months less a day after our 
start from Balboa. Our cruise across the Pacific 
was finished. 
SUMMARY OF RESULTS 
During our Pacific cruise 57 cores with an 
integral length of nearly 500 meters have been 
taken, most of which display more or less dis¬ 
tinct stratification. In most, but not in all, cases, 
the sediment profiles raised by means of the 
long piston core sampler have been supple¬ 
mented by cores from the surface layers taken 
by means of a short core sampler of Dr. Phle- 
ger’s construction and kindly loaned by him for 
the duration of the cruise. 
According to the technique developed by Dr. 
Kullenberg, the cores are extricated from thin 
lining tubes 70 centimeters in length inside 
the steel coring tube and, after a cursory exami¬ 
nation on board, are wrapped first in briophane 
and then in pergament paper. These wrapped 
cores are introduced into aluminum tubes filled 
with molten paraffin wax and stoppered, after 
which they are placed in cool storage, between 
5° and 8° G, pending analysis after our return 
to Sweden. Experience shows that cores pre¬ 
served in this manner remain practically un¬ 
changed indefinitely. 
Sediment soundings by depth charges have 
been carried out at 75 different positions, where 
in most cases, two depth charges were set to 
explode at different depths (500 and 2,500, 
4,500, or 6,500 meters). Only between Balboa 
and the Galapagos were reflexes recorded from 
depths below the surface of the sediment sen¬ 
sibly deeper than 300 meters. For this striking 
difference between our results in the Atlantic 
and in the Pacific, no explanation can yet be 
offered. 
Four complete hydrographic sections have 
been made across the Equatorial Countercurrent 
System, yielding results similar to those indi¬ 
cated above. When worked up from the dy¬ 
namic point of view these sections, supple¬ 
mented by frequent bathythermograph sound¬ 
ings between the stations, will afford valuable 
material for the study of the Equatorial Counter- 
current and the accompanying strips of conver¬ 
gence and divergence. 
At a few deep stations large-volume water 
samples of 25 liters were taken from different 
depths for analysis for radium (by the BaS0 4 
Mitreissreaktion) and uranium (by fluor¬ 
escence). Such analyses are necessary for con¬ 
firmation of the ionium precipitation hypo¬ 
thesis set forth by the author in 1936 
(Pettersson, 1937), and subsequently substan¬ 
tiated through the work of C. S. Piggot and 
W. D. Urry (1939: 405; 1941), and also in 
order to utilize measurements of radium in the 
sediment for determining the rate of sedimen¬ 
tation in the upper layers (Pettersson, 1943, 
1945). 
Optical studies on sea water were carried 
out, partly by direct measurements of sub¬ 
marine daylight in different spectral ranges 
down to depths of 100 meters, and partly by 
photographic methods down to greater depths 
by means of a pressure-tight submarine camera. 
In addition ultraviolet components have for the 
first time been measured near the surface in 
the open sea by means of a special technique 
(Johnson, 1946). Finally, the amount of 
suspended particles at different depths was 
measured by means of the Tyndall method, 
using samples obtained with specially prepared 
water bottles. Interesting results which show 
the occurrence of distinct maxima of such par¬ 
ticles at certain depths were found by these 
measurements. 
The records from our echo sounder have al¬ 
ready been referred to. When worked up 
systematically, results of value both from a 
bathymetrical and from a morphological view¬ 
point may be expected. An interesting obser¬ 
vation made repeatedly when crossing the bands 
of convergence bordering the Equatorial Coun¬ 
tercurrent was extra reflections on the echo- 
gram in depths between 80 and 150 fathoms. 
These reflections indicate densely packed or- 
