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. It would, too, be interesting to investigate whether Auroræ and ozone development are respectively localized. Mr. Ingall’s fine Aurora, seen at Champion Hill, S.E., July 18th, 1874 (_antè_, pp. 22 and 23), was not observed at Frant, and the ozonoscopes there were described as blanched by antozone. APPENDIX E. INQUIRIES INTO THE SPECTRUM OF THE AURORA. BY H. C. VOGEL.[18] The frequent appearance of the Aurora in the past winter, as well as this spring, has given me opportunity to institute exact inquiries into the spectrum of the Aurora. It is known that the nature of Auroræ is as yet but little explored. It has been considered necessary to abandon the former view—that they are discharges of the electricity collected at the poles—because it has been hitherto found impossible to bring the chief lines of the Aurora-spectrum into coincidence with the spectra of the atmospheric gases. Theoretical considerations, based on the great alterations to which the spectrum of the same gas is subject under varying conditions of temperature and density, have very recently led Zöllner to the opinion that probably the spectrum of the _Aurora does not coincide with any known spectrum_ of the atmospheric gases, only because it is a spectrum of another form of our atmosphere hitherto incapable of artificial demonstration[19]. The following article will show how far I have succeeded, in conjunction with Dr. Lohse, in supporting this view by exact observations of the Aurora-spectrum itself, as well as by comparison with the spectra of the gases constituting the air. The star-spectrum apparatus belonging to the 11-inch equatorial of the Bothkamp Observatory was used for these observations. It consists of a set of prisms _à vision directe_, five prisms with refracting angle 90°, slit, collimator, and observing telescope. The lowest eyepiece (magnifying four times) of this telescope was employed. The telescope is capable of being moved in such a way, by the aid of a micrometer-screw, that different portions of the spectrum can be brought into the centre of the field of vision. As fractions of the rotation of this screw are marked, the distances of the spectral lines can be readily found.