Observed in the amount of Oxygen in the Air. 419 
Oxygen found in the Air at Hudson, Ohio, from January to April, 1881. 
January, 1881. February. March. April. 
Date.| Oxygen. |Date.| Oxygen. |Date. | Oxygen. Date.) Oxygen, 
949 939} 1 |958 961 | 1 ‘948 953| 1 |972 972 
18/936 940] 2 |959 953 2 (950 956) 2 |974 975 
2 (954 960! 3°1954 960 3 |967 3 1965 964 
2°1952 947) 4 1952 962 4 |961 962} 4 |967 968 
3 {959 957] 56 1964 959 5 1962 969; 5 1970 973 
4 |954 951) 6 1949 962 6 |958 962| 6 |972 974 
5 |958 958! 7 |963 963 7 |969 969} T |973 968 
6 1956 953 - 966 seat 8 |964 2; 8 |962 972 
7 |958 948) 8 |968 965 9 |965 963} 9 |962 966 
8 |946 96 9 9 956 10 |955 962] 10 |967 971 
9 4.962} 10 |951 950 | 11 |967 966) 11 |963 971 
10 |966 96 1 (950 946 12 (948 959] 12 |966 967 
12 |963 956} 13 |953 951 14 (9 4 |973 971 
13 |958 957) 14 |948 957 | 15 (962 965) 15 |975 970 
14 |957 961) 15 |958 962 | 16 |9 6 |968 970 
15 |960 961) 16 |951 17 |960 963] 17 |970 966 
16 |952 952) 17 |961 967 18 (972 965) 18 |969 
17 |959 957] 18 |955 962 |"19'2/960 960] 19 |964 960 
18 |950 952) 19 |959 961 | 20 |956 954) 20 |969 963 
9 |956 956) 20 |957 954 1 |974 974 
0 |958 960} 21 |961 968 a 9ST 907 
1 |948 950} 22 |950 954 8 {970 970 
2 |938 933] 23 |968 962 4 |970 967 
3 |955 947] 24 |963 972 5 |967 969 
4 |959 958] 25 |959 961 26 |960 962 
25 |952 947) 26 |958 959 | 27 |962 963 
26 \969 967) 27 |9 28 \976 977 
27 1959 959, 28 |943 950 | 29 |952 955 
28 |953 961 30 (957 959 
29 |960 954 $1 |973°97Z 
30 |968 964 
31 |960 962 
sie eshaghe in the a “Oxygen” are the 3d, 4th and Sth decimal Loar 
futons which are to be supplied mor decimal point, followed by the figures 20. 
For pga 956 signifis 0°20956. But on ar 9, 1880, supply 0-21. . col- 
lected at Bd 5. 6% collected at 1) 2 4, 5, 8, 9, P.M; *, second | 
ple p ebllacted taae at the same time as the seating sample. 
winds at the stations of the Service all radiating from this center, 
especially if their velocities are considerable, we may infer with 
some fair proven that within this area of radiation there 
was a descent of air from an elevation. 
I have, therefore, examined the Signal Service maps of the 
date of each deficiency in oxygen, or of each noteworthy fall in 
