EF. Loomis— Observations of the U. S. Signal Service. 11 
observation, oe less than half of what it was at an intermediate 
date. the average temperature of the winds on the 
north side of ca low area was 9°5 degrees below the mean for 
that time and place; and the average temperature of the winds 
on the south side of the low area was 14-7 degrees above the 
mean for that time and place. In table III the average tem- 
perature = the winds on the north side of the low area was 12 
egrees below the mean, and on the south side was 17 degrees 
above a mean. The blanks in columns seven and eight of 
table IIT result from the center of least pressure being near the 
boundary of the United States, so that the signal service sta- 
tions do not furnish the required data. In both tables the 
average humidity of the north winds was nearly the same, but 
the humidity of the south winds was very much the greatest in 
— II. In table IT the average velocity of the south winds 
en per cent greater than that of the north winds. In 
eee III the average velocity of the north winds was about 
double that of the south winds. In table II the average rain- 
fall in eight hours within the low areas was 6°89 inches; in 
table ITI the average rain-fall was 0°57 inch, and in a majority 
of the cases Pe ~~ table the average rain-fall in eight hours 
was only 0-14 
The most emarkable circumstance which characterizes these 
two classes of storms is the difference in the amount of rain-fall. 
In the cases shown in table II the rain-fall was enormously 
great, and this appears to be the general characteristic of those 
storms which originate near the Gulf of Mexico. In my 
seventh paper, I gave a list of all the cases contained in the 
volumes of the Signal Service observations which had then been 
ublished, showing a total rain-fall of eight inches in eight 
ase at all of the stations. More than two-thirds of all these 
storms originated on or near wots Gulf of Mexico, and a major- 
it of the remaining cases occurred in summer. One reason 
why these storms are attended ea a great fall of rain appears to 
be that the south wind is charged with a large amount of vapor 
from a warm sea. From table II it appears” a this south 
wind is warm, moist, and pushes northward with great force. 
The principal object which I had in view in preparing these 
tables was to discover, if possible, the reason why these storms 
pursued so unusual a path. The average course of the eight 
storms in table II was only 20 degrees east of north. One of 
them moved almost exactly north, and another deviated sensibly — 
to the west of north. Can any reason be assigned for this un- 
— course? I have endeavored to determine whether there 
connection between the course of the storm and the 
rere § which accompanied it. Plate I of my 7th Sept 
shone the curves of — rain-fall for the eight hours preceding 
