422 E. W. Morley— Cause of the Variations 
Feb. 10, 7 A. M—High pressure now prevailed off the coast 
of New England. The form of the isobars and the directions 
of the winds reported show a gentle current of air along the 
eastern slope of the Appalachians, but no motion across them. 
The crowding together of isobars running along the axis of the 
mountains, as well as the uniform northwest motion of the 
winds over an area reaching from Cincinnati to Oswego and 
Kingston, make it probable that air from an upper current 
came down to the surface of the earth near lake Hrie; and the 
oxygen found here at 9 A. M. was 020929. 
Feb. 11, 7 a. M.—At this hour there was an area of high ba- 
rometer over Chesapeake Bay. ‘The winds were all moving 
away from the Appalachians, both on the eastern and the western 
slopes. It is therefore likely that there was a descent of air 
from some upper current. The oxygen found here at 9 A. M. 
was 0°20942. 
Feb. 12, 7 a. M.—There was now an area of high barometer 
off the coast of South Carolina. Hast of the Appalachians most 
of the winds were parallel to the axis of the chain. est of 
the mountains the winds may well enough have come from the 
Gulf of Mexico, but the acceleration of the winds as we look 
toward the center of low pressure near the upper lakes may 
perhaps indicate a descent of upper currents. The oxygen 
found at 9 a. M. was 0'20934. 
On Feb. 13th the oxygen found was 0:20897 ; this case needs 
special discussion. 
Feb. 20, at 7 a. m.—There was an area of high pressure hav- 
ing its center near Pittsburgh. Winds radiated in all direc- 
tions from this center. The inference of the descent of upper 
currents is probable. At 9A. M. the amount of oxygen found 
here was 0°20930, and in another sample taken at nearly the 
same time, 0°20925. 
the two hours of observation next following the one just 
mentioned, the same divergence of winds from a center seems 
to have continued, the center passing slowly to the east. Now 
at 7 A. M. on the 2ist, no such condition of radiating winds 
continued, but the oxygen found at 9 A. M. was 020926. Pos- 
sibly the long continuance of conditions favoring the descent 
of upper currents had brought to the surface of the earth near 
this place a volume of air poor in oxygen which had not yet 
been carried away under succeeding conditions. 
February 22d.—At 7 A. M. there was an area of high bar- 
ometer a little to the south of the Ohio River. At 9 A. M. 
the oxygen found here was 0°20934, and in another sample 
0:20918. 
A deficiency of oxygen was also observed on February 26th, 
and on March 11th, 12th and 15th, but I am able to suggest no 
satisfactory explanation of either case. 
