+-------------------+----------+------+------------------------+ | Date. | Aurora. |Ozone.| | +-------------------+----------+------+------------------------+ |1870, October 14th.|Aurora. | 8 |The display of the 24th | | ” ” 20th.|Aurora. | 10 | was accompanied by | | ” ” 21st.|None seen.| 5 | the formation of a | | ” ” 22nd.|Aurora. | 10 | corona, and that of | | ” ” 23rd.|None seen.| 8 | the 25th was splendidly| | ” ” 24th.|Aurora. | 10 | seen in Edinburgh. | | ” ” 25th.|Aurora. | 8 | | +-------------------+----------+------+------------------------+ The foregoing figures somewhat point to the conclusion that ozone quantity rises and falls coincidently with the Aurora displays. The following seems, however, a case still more strongly in point. +-------------------+-------+---------------------+------+ | Date. | Wind. | Aurora. |Ozone.| +-------------------+-------+---------------------+------+ |1871, January 25th.| E.S.E.| None seen. | 0 | | ” ” 26th.| N.N.W.| None seen. | 2 | | ” ” 27th.| E.S.E.| Aurora at night in | | | | | N. and S. horizons.| 10 | | ” ” 28th.| E. | None seen. | 8 | | ” ” 29th.| S.E. | None seen. | 2 | +-------------------+-------+---------------------+------+ It is curious, in examining the above Table, to note how the ozone rose, notwithstanding an east wind, from 0 on the 25th, and 2 on the 26th, to 10 on the 27th, when the Aurora appeared, and 8 on the 28th, when it might have lingered; and how it again descended to 2 on the 29th. The case of the Aurora of 6th of October, 1869, when a broad belt of Aurora was in the north, is also an illustrative one, as will be seen by the following data:— +------------------+------+------+-------+ | Date. |Wind. |Ozone.|Aurora.| +------------------+------+------+-------+ |1869, October 5th.|S.S.W.| 1 | — | | ” ” 6th.|S.S.E.| 5 |Aurora.| | ” ” 7th.|S.S.W.| 10 | — | | ” ” 8th.| S. | 10 | — | | ” ” 9th.| S.E. | 5 | — | +------------------+------+------+-------+ The Aurora of the night of the 6th was here represented by the ozone-paper of the morning of the 7th with a maximum of 10, which lasted till the 8th. [It should be borne in mind, in examining these Tables, that the Aurora is of the night of the given date, while the ozone-papers are taken and recorded in the morning of the date quoted.] [Sidenote: Other instances.] We will now take instances where the ozone has not reached its maximum; but even in these cases a certain amount of rise and fall of the ozone development towards and from the Aurora is traceable.