422 
PACIFIC EXPLORATION: C. F. MARVIN 
courses. Observers at sea on such occasions have but scant oppor- 
tunity or incentive to engage in serious scientific observations, and 
difficult investigations are impossible. Consequently, what has been 
obtained in the past through these opportunities, and what may possibly 
be thus obtained in the future, is Kmited and restricted in every way, 
that is, Kmited as regards the kind and quantity of data that may be 
obtained, and restricted as to the region or locaHty to which it appHes. 
A proposal to launch and equip an expedition to make a scientific 
exploration of the Pacific Ocean is, therefore, hailed by the meteorolo- 
gists with enthusiasm. 
The aerological investigations now being made at a very few continen- 
tal stations by means of kites and balloons constitute but a fragment 
of the evidence and data needed to exhibit the more detailed features 
of the circulation of the atmosphere. Data from and over the ocean 
can be obtained only by means of vessels devoted exclusively to scienti- 
fic investigations, and the vast stretches of the Pacific, dotted with its 
occasional islands that afford useful vantage points as bases of reference, 
offer a field for such explorations unsurpassed elsewhere. 
To state the proposal and indicate the objects of the exploration seem 
to be all that is necessary to enlist the fullest support thereof. It 
offers to meteorology the only opportunity possible to obtain full and 
complete observational data prepared by experienced and competent 
observers quahfied to conduct the difficult exploration of the free air 
now so much needed. With the few exceptions previously alluded to, 
upper air explorations have been made only at a small number of con- 
tinental stations, located at a few points in England, France, Italy, 
Belgium and Germany. These, in a sense, constitute only a small 
group in the aggregate and are supplemented by a few additional de- 
tached points of observations in the United States. 
Both the surface and the free air observations from the ocean are 
valuable in themselves as supplementing the corresponding continental 
data, but the opportunity presented by a special expedition moving 
from point to point in both latitude and longitude on the greatest of 
all oceans permits of extending observations by the same standard 
methods to those regions from which the information is most valuable 
and most needed. 
Progress in the development of our knowledge of the upper air and 
its general circulation awaits accurate observations by the aid of kites 
and balloons. The scanty observations from a few stations on limited 
and scattered continental areas show that the atmosphere arranges 
itself in two or more well-defined layers of different characteristics and 
