Observed in the amount of Oxygen in the Air. 423 
March 24th.—At 7 A. M. there was an area of high pressure 
having its center at Lake Superior. Winds were diverging all 
around the southern half of a circle; no stations were far 
enough to the north to give any certain knowledge as to their 
direction over the northern half. The oxygen found here at 9 
A. M. was 0°20942. 
The same remark may be made as to March 30th. A center 
of high pressure existed near Lake Superior, and the winds 
radiated from the southern half of acirele. Theoxygen found 
at 9 A. M. was 0'20922. . 
April 9th.—At 7 a. M. there was an area of high barometer 
reaching from Texas to Tennessee. North of latitude 37 de- 
grees, and east of St. Louis, almost every reported wind was 
blowing toward the north or northeast, while on the south of 
the same line the winds reported were all blowing toward the 
south or southwest. We may therefore suppose that some de- 
scent of upper currents would occur; at 9 A. M. the oxygen in 
the air here was 0°20940. 
April 14th.—At 7 A. M. there was a center of high pressure 
off the coast of Georgia, but the data are too incomplete for 
trustworthy inference. The oxygen found at 9 a. M. was 
020945. On the 16th, tie data are also too incomplete. 
April 28th —At 1 A, M. there was an area of high pressure 
with distinctly radiating winds having their center on the Ohio 
iver. At 7 A. M. this center was over West Virginia. At 9 
A. M. the oxygen found in the air here was 0°20957, which was a 
fall of 0:00012. The cause continued to operate for some time 
afterwards, and on the next day the oxygen found was 0:20941. 
On the 80th, in spite of the passage of an area of low barome- 
ter the oxygen continued low, being found to be 0:20943. On 
May 1st there was a center of radiating winds over the south- 
east part of Kentucky. Under the influence of the descent of 
upper air which probably occurred, the oxygen found at 9 A. M. 
was 020947. 
On the 2d this center of radiating winds was over North 
Carolina, and the oxygen found here was 0°20932‘at 9 A. M. 
On the 9th and 10th an area of high barometer hovered over 
the sea coast of North Carolina for twenty-four hours, with 
well marked diverging winds over the observed half of the cir- 
cumference of a circle. On the 9th the oxygen found here was 
0-20944, and on the-10th it was 020950, both at 9 A.M. An 
area of high pressure now developed near Lake Michigan and 
hovered to the north of the lower lakes till the morning of the 
16th, when it passed over the lakes toward South Carolina. 
During these days the oxygen found here at 9 A. M. was 
920950, 020953, 0°20951, 0°20951, and 0-20948, and on the 
16th when the area of high pressure became central near Cleve- 
' land, the oxygen found at 9 A. M. was 0.20927. 
