594 
MR, J. NORMAN LOCKYER ON THE 
being submerged in continuous spectrum, which is relatively more intense in the case 
of the prismatic camera, Further, as already pointed out, it is not yet established 
that many of the lines recorded in the corona by the slit spectroscopes are not due to 
glare. 
By a comparison of the results obtained with slit spectroscopes and prismatic 
cameras, it would seem to be possible to determine which of the lines recorded by the 
former instruments really belong to the coronal spectrum. The most intense light 
will give the strongest glare, and therefore the brightest lines of the chromosphere 
and prominences will become superposed on those due to the corona. As the results 
obtained with the prismatic cameras are so very definite with regard to the spectrum 
of the prominences, it seems only necessary to subtract the common lines of the 
spectra recorded by the two instruments from the total number recorded by the slit 
spectroscopes in order to determine those which certainly belong to the corona. 
An attempt has been made to investigate the coronal spectrum in this way by 
reference to the slit spectra of 188G and 1893, but no satisfactory results can be 
obtained in this way until slit spectra taken with greater dispersion become available. 
In the case of the rings, the evidence that they truly belong to the corona is 
absolutely conclusive. 
Comparison with Fraunhofer Spectrum. 
In the absence of more exact knowledge of the wave-lengths of the radiations 
producing the rings, it is not yet possible to determine if they are represented by 
dark lines in the Fraunhofer spectrum, but it can already be stated that, if present 
at all, they are among the feeble lines. 
Comparison with Prominence Spectrum. 
A point of some importance is the apparent absence of the 1474 K ring from the 
spectra of the chromosphere and prominences. A similar absence of 1474 K from 
the prominence spectrum was noted by Bespigei in the eclipse of 1871. I am not 
aware of any observation in which the form of a prominence has been observed in 
1474 light. All these facts seem to indicate that when the 1474 is observed at the 
sun’s limb without an eclipse, the spectrum of the corona itself is under examination, 
under the same conditions as those recorded in the eclipse photographs. 
Of the other coronal rings photographed in 1893, those at wave lengths 4217 and 
4280 are approximately coincident with feeble prominence radiations, but since the 
other coronal rings are not represented in the prominences, the coincidences may be 
regarded as accidental. 
Although H and K are by far the most intense of the radiations of the prominences, 
on no occasion have they been photograpned as rings in the spectrum of the corona 
with the prismatic cameras. They have, however, been occasionally recorded as 
