624 KANSAS CITY REVIEW OF SCIENCE. 
We know that there is a greater barometric pressure over the parallel of lati- 
tude 32°, than at the Equator or at 64°. It is assumed that from latitude 32°, 
and from the poles, the suction of the atmosphere is towards each other. The 
meeting place may be at latitude 64°, theoretically, but by reason of terrestrial 
influences this meeting point may be considerably south of that, in fact may be 
over a debatable ground between parallels 40° and 60° of North America, but 
higher over the Atlantic Ocean. This would make the cause of low barometer, 
and the resultant of the force exercised by two areas of higher barometer. For 
if a wind, blowing at the rate of twenty miles north meets a wind blowing at the 
rate of twenty miles west, there will be produced either a wind which shall be in 
proportional direction and velocity to the two causing it, or else it will produce a 
system of vortices in the direction resultant of the two, but of no fixed velocity, 
especially if these winds are believed to decrease in power as the distance from 
the originating area increases. 
In dealing with such an elastic medium as the air and with the imperfect 
data at our command it is impossible to say how the no doubt daily reinforce- 
ment of wind pressure from the originating lands should provoke a disturbing 
area about once in three days along their meeting line. 
If instead of actual motion from latitude 32° and from the poles we think of 
two undulations (deflected by the rotary motion of the earth, the one to the east 
the other to the west), I think we have a basis upon which a theory of the 
cause of low barometer may be formed capable of arithmetical calculation as to 
force and direction. I do not wish to seem to explain too much in one argument 
nor yet to suggest too recondite a system of weather predictions, but upon some 
such grounds as these must, I think, the future meteorolgist stand who will pre- 
tend to be able to foretell, more than a few hours in advance, changes and con- 
ditions. 
Whether atmospheric pressures can ever be formulated into such mathemat- 
ical precision that weather conditions can be predicted as certainly as astronomi- 
cal changes I am inclined to doubt. I fear meteorology will always remain an 
empiric rather than an abstract science. With the accumulation of facts general 
principles are formulated, but they more and more take the form of contingencies. 
As in our judgment of men we trust more to experience and comparison than to 
an ideal scale of possibilities, so, in weather knowledge, short views and cautious 
application of general laws are more frequently correct than more pretentious fore- 
casts. It is only with casual phenomena that practical meteorologists care to deal, 
and of these temperature is the one of most popular interest. This subject is 
next in order to be considered. 
Temperature. — It may be hardly necessary to say that outside of the Signal 
Office at Washington, with its tables and charts at hand, and its corps of trained 
assistants, no one can expect to make a weather prediction which shall be more 
than probably correct, and that for only a brief period in advance. Even with- 
out the special training and facilities of the central office there is a tendency to 
