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.

Date.Wind.Ozone.Aurora.
1871,April8thS.S.E.5Aurora on 9th, but wind E. and unfavourable to ozone.
””9thS.S.E.8
””10thS.E.5
1871,November9thN.5Aurora on all three nights.
””10thN.W.8
””11thN.5
1872,February3rdS.W.4Aurora on night of the 4th represented by ozone-paper of morning of the 5th.
””4thS.S.W.5
””5thS.W.8
””6thS.W.5

Other cases are, we are bound to say, found, in which ozone was either not remarkable for quantity, or positively fell during the Aurora, as, for instance, this:—

Date.Wind.Ozone.Aurora.
1874,March16thW.N.W.6Aurora on the 18th represented by test-paper of the 19th with only two degrees of discoloration.
””17thS.W.6
””18thW.5
””19thS.S.W.2

It is, however, possible that such instances may be accounted for, either by some reaction on the test-papers after they have been coloured, or by some accidental antagonistic circumstance affecting the tests. The following is a case well illustrating this:—

Date.Wind.Ozone.Aurora.
1874,January31stN.N.W.6There was an Aurora on the night of the 2nd represented by the ozone-paper (4 only) on the morning of the 3rd.
”February1stN.W.8
””2ndN.W.2
””3rdN.N.W.4
””4thE.N.E.8

This instance would seem strongly opposed to the theory of a connexion between Aurora and ozone but for the fact that on the 2nd, when the Aurora was seen at night, and on other days in the same month, Dr. Allnatt has recorded a strong wave of antozone to have swept over the whole of England, and blanched the ozone-papers, however deep their coloration might have previously been. Indeed, it is easy to understand that some antozonic influence may, at times, disturb the evidence of the test-papers, even in so elevated and apparently pure an atmosphere as that of Frant.

It may not be considered that the foregoing instances are enough to establish a case of ozone=Aurora; but there seems, at least, sufficient to base a requisition for further inquiry upon.