1920 .] Adams and Marsden. — The Samoan Observatory. 
161 
A recording tide-gauge is maintained by the observatory in Apia Harbour, 
and several interesting records of tidal waves have been obtained. 
(3.) Astronomical Observations. —The astronomical observations are— 
(a.) Local time service. Time determined by meridian transits of sun 
and stars, with a transit instrument of 2 in. aperture and 24 in. 
focal length. The observations are by eye and ear with a sidereal 
chronometer. 
(A) Spectrograph observations of the zodiacal light. 
(c.) Observations of the sun and of solar eclipses. 
It was the intention of the former controllers of the observatory to install 
instruments for the absolute measurements of total solar radiation, as it 
has been found that the variations of this radiation have a very direct 
influence on the magnetic elements and the seasonal variations in the 
meteorological conditions. 
(4.) Meteorological Observations .—The ordinary meteorological elements, 
barometric pressure, temperature, rainfall, and humidity, are recorded with 
an unusually high order of accuracy. As a result of the close observation 
of these high-grade records interesting periodicities in the seasonal weather 
conditions have been revealed, and important correlations with magnetic, 
seismic, and solar activities. It is hoped that particulars of these connections 
will be published in the near future. 
(5.) Aerology .—Observations of the upper atmosphere have been made 
since 1906. Hand-hauled kites containing instruments to register height, 
temperature, wind-velocity, and humidity were flown on all “ international” 
days, 1906 to 1914, and the results published internationally. Heights 
up to 7,000 ft. were reached. Free balloons were also liberated, and their 
movements followed by theodolites to about 40,000 ft. to obtain wind- 
velocities at great heights. The results indicate a return westerly wind 
above the level of the south-east trade-winds. The exact relations as regard 
level, &o., between this returning westerly wind and the surface wind still 
require further investigation. This should be concentrated on in future 
because of its importance in relation to aerial navigation. Four publications 
of summaries of investigations have been made by Dr. Angenheister and 
Dr. Wegener in the Gottingen Nachrichten, embodying results up to 1910. 
No upper atmosphere observations have been made since 1914. It may 
be noted that just about the time the war broke out arrangements had been 
made with the German Navy for the co-operation of a destroyer in chasing 
balloons carrying instruments to record automatically the temperature and 
wind-velocity and direction at different heights. 
(6.) Atmospheric Electricity. —This study was commenced at the observa¬ 
tory in 1905. Measurements are made every day of the number and the 
mobility of the positive and negative ions present in the atmosphere. 
Continuous records are made of the vertical potential gradient, and also of 
the electric charge of rain and the earth-air electric current. Measurements 
are also made of the amount of radio-active matter in the atmosphere, both 
that derived from radium and that from thorium. Improved observational 
methods of the measurements of these important factors are indicated as the 
result of the experience obtained. It is most important that the atmo¬ 
spheric electricity observations should be carried on energetically in the 
future because of their possible bearing on aerial navigation and on 
agriculture. A critical summary of the chief results up to date is also 
urgently required. 
Enough has been written above to indicate the importance of maintain¬ 
ing the Samoan Observatory at its full pre-war efficiency, and it is to be 
sincerely hoped that means will be found to continue the work and thus reap 
full advantage of the previous experience and results. 
11—Science. 
