Comparison of the lines.
The nearest approaches to Captain Maclear’s lines (of the upper spectrum) which I can find are:—
| Line | Corresponding line. |
|---|---|
| 1. | 5567, Ångström. |
| 2. | (The faint line.) Vogel’s band, 4694-4629. |
| 3. | I find no approximately corresponding line. |
| 4. | 4350, Alvan Clarke. |
But the comparisons are not by any means close. Further observations of the Australis spectrum are very desirable.
Prof. Piazzi Smyth’s Aurora-Spectra.
Prof. Piazzi Smyth’s chemical and auroral spectra.
Prof. Piazzi Smyth, in volume xiv. of the ‘Edinburgh Astronomical Observations,’ 1870-77, has compared simultaneously the Aurora-spectrum with the sets of bright lines seen in the blue base of flame—the lines of potassium, lithium, sodium, thallium, and indium being also introduced for comparison. The spectra are drawn as seen under small dispersion, and will prove most useful in cases where an Aurora is not bright enough to admit of the lines being measured by micrometer, and the eye and comparison spectrum are obliged to be resorted to.
Plate XII.