346 
the four formulz; for the reasons already given, the fifth and 
most correct formule cannot be used in practice :— 
Tas_e II. 
No. I. II. | Ill. IV. ben tipo ne 
yet) aod 4, P.M. | 
1| 155°30 | 156-54 | 156-38 | 157-63 ~ 029 
2) 15913 | 160-88 | 157:39 | 15912} +-013 
3) 156-56 | 157-81 | 155-93 | 157-18 | +-094 
4| 159-00 | 160-43 | 159-22 | 160-65 | +-026 
5| 156-61 | 157-86 | 150-30 | 15150| +-044 
6| 157-25 | 157-51 | 160-25 | 161-53 —-092 
7| 156-70 | 158-11 | 153:19 | 15457 | —-061 
| 8] 15876 | 159-87 | 160-41 | 16153 | +-034 
9| 160:87 | 163-28} 159-12 | 16150} —-157 
10| 157-53 | 159-26 | 157-49 |- 15922 | —-069 
157-771 | 159-155 | 156-968 ae 
On examining column I. of these observations, it is plain 
that they may be divided into two distinct groups, of which 
Nos. 1, 3, 5, 6, 7 are below the average, and Nos. 2, 4, 8, 
9, 10 are above the average. Of the latter, Nos. 2, 4, 9 were 
made on wet days; Nos. 8, 10, on windy days, and in all, the 
state of the atmosphere may be considered as unsettled; al- 
though, so far as the change in the barometer is considered, 
Nos. 2, 4, 8 will bear comparison with the fine days. 
If we take the mean results of the observations on settled 
and unsettled days, we obtain the following Table :— 
Tasure ILI. 
| rE IL. III. IV. | 
Sapa oe 156-484 | 157-566 | 155-210 | 156-482 | 
Unsettled,. . . .}| 159-058 | 160-744 | 158-726 naa 
Column ITI. is less than I. for the reason already given. 
Comparing columns I. and IV., it is interesting to observe 
