PACIFIC EXPLORATION: C. F. MARVIN 
421 
salinity, and density. That is to say, the waters have a gradual in- 
crease in density from the surface to the bottom, a gradual decrease in 
salinity from the surface to the bottom, and a gradual decrease in tem- 
perature from the surface to the bottom. But the details of the dis- 
tribution of these quantities is unknown; of their variations from season 
to season and from year to year few observations have been made in the 
depths of the Pacific, and there is as yet very limited knowledge of the 
import of such changes upon the variations of climate and of physical 
and biological oceanography. 
The observational foundation for investigating the ocean from the 
standpoint of thermodynamics requires the study in detail of definite 
stations occupied in concert and periodically revisited for the purpose 
of observing, as nearly as possible at the same time, such physical 
conditions, at certain depths, as the temperature, the salinity, the gas- 
content, and the currents; and in this way affording the means of pre- 
senting in the form of synoptic charts the changing network of lines of 
equal values of the physical elements in their distribution in the depths. 
To sum up our thoughts, we may fix attention (1) upon the basin, 
of which no model can be at present constructed; (2) upon the deposits, 
whose thickness and stratification still remain unrevealed; (3) upon the 
waters, whose variations in physical conditions have not yet been 
sufficiently observed to explain the inner mechanism by which they 
operate to produce their effects in the economy of the earth. 
MARINE METEOROLOGY AND THE GENERAL CIRCULATION 
OF THE ATMOSPHERE 
By Charles F. Marvin 
U. S. WEATHER BUREAU, WASHINGTON, D. C 
Read before the Academy, April 17. 1916. Received June 13. 1916 
Stations for the surface observation of meteorological conditions are 
now numerous in the principal civilized countries of the world, and 
within the past twenty-five or thirty years explorations and investi- 
gations of the free upper air have been actively conducted at a number 
of places on land. In a few instances soundings of the air have been 
made on the North Atlantic ocean and in waters adjacent to Europe 
under the initiative of the late A. Lawrence Rotch, Teisserenc de Bort, 
and others. As a whole, however, little is known in detail of the meteor- 
ology of the oceans, except as revealed by the simple observations of 
weather and wind which many merchant and naval vessels have been 
accustomed to report for a number of years while plying their regular 
