Observed in the amount of Oxygen in the Air. 421 
ture for the region had become colder. It is, therefore, highly 
probable that some Secchi of air from an elevation entered the 
area; and at 4 p. M. the oxygen found here was 
Jan. 18, 3 P. ete the directions of the Ae on the 
map of this date we could not be sure that the currents of air 
passing over Ohio had not come from the Gulf of Mexico after 
passing around a center of high pressure. But the maps for 
forty hours previously make it “reasonably sure that no currents . 
at the surface of the earth had brought air from the Gulf of 
Mexico to the vicinity of Cleveland, and so lead us to infer that 
the sample collected here at 4 P. M. was from air spreading idee 
in all directions from the center of high pressure just men- 
tioned, which was over the States of Mississippi and ‘Tes aween 
It contained 0°209389 oxygen 
The deficiency of oxygen “found on January 21st is consis- 
tent with the theory proposed, but affords no evidence. 
Jan. 26, 7 a. M.—There was an area of high barometer over 
the seaboard from Vi rginia to Maine. Over the southern part 
of Pennsylvania there was an obvious center of winds radiating 
in all directions with a mean velocity of about five miles an 
hour. It is probable that the withdrawal of air from this area 
was made good by the entrance into it of air from some upper 
current. At9 A.M. the amount of oxygen in the air at this 
place was 0° 20081. 
an. 29,3 Pp. M—At this time there was an area of high 
barometer having its center a little to the northwest of Mon- 
treal. The same point seems also to have been a center from 
which winds ratiaed in every direction. Although there are 
no stations reporting from the northern half of the supposed 
circle, a circular course of isobars is derwe indicated; the 
winds to the east of the center blow to the east, and those to 
the west of the center blow due ok The mean velocity of 
winds passing out from the southern half of the assumed circle 
is ten or twelve miles an hour. If, then, there was a closed 
curve to the ions, where the air was also passing out, there 
must bave been a rather rapid supply of air brought into this 
area by currents from an elevation, and at 9 A. M. the oxygen 
found at this place was 0°20926. 
Feb. 9, 7 A. M.—There was at this time ‘an area of high ba- 
rometer within abi the isobar of 30°40 inches was uearly!a 
circle having Lake Michigan for its center. Stations are but 
few to the north and northwest of this circle, so that it;cannot 
ms estorge nid affirmed that winds were blowing outward all 
und the circumference. But the Sah cs of the winds 
ore the northern half of the ele and the briskness of winds 
passing over its southern sence point to a aioe 
of upper currents. The oxygen found here at 9 A. M. 
914. 
0-20 
