TOTAL ECLIPSE OF THE SUN, APRIL 16, 1S93. 
609 
(10.) There is distinct evidence of periodic changes of the continuous spectrum of 
the corona. 
(11.) Many lines hitherto unrecorded in the chromosphere and prominences were 
photographed by the prismatic cameras. 
(12.) The preliminary investigation of the chemical origins of the chromosphere 
and prominence lines enables us to state generally that the chief lines are due to 
calcium, hydrogen, helium, strontium, iron, magnesium, manganese, barium, chromium, 
and aluminium. None of the lines appears to he due to nickel, cobalt, cadmium, tin, 
zinc, silicon, or carbon. 
(13.) The spectra of the chromosphere and prominences become more complex as 
the photosphere is approached. 
(14.) In passing from the chromosphere to the prominences some lines become 
relatively brighter but others dimmer. The same line sometimes behaves differently 
in this respect in different prominences. 
(15.) The prominences must be fed from the outer parts of the solar atmosphere, 
since their spectra show lines which are absent from the spectrum of the chromo¬ 
sphere. 
(16.) The absence of the Fraunhofer lines from the integrated spectra of the solar 
surroundings and uneclipsed photosphere shortly after totality need not necessarily 
imply the existence of a reversing layer. 
(17.) The spectrum of the base of the sun’s atmosphere, as recorded by the pris¬ 
matic camera, contains only a small number of lines as compared with the Fraunhofer 
spectrum. Some of the strongest bright lines in the spectrum of the chromosphere 
are not represented by dark lines in the Fraunhofer spectrum, and some of the most 
intense Fraunhofer lines were not seen bright in the spectrum of the chromosphere. 
The so-called “reversing layer” is, therefore, incompetent to produce the Fraunhofer 
spectrum by its absorption. 
(18.) Some of the Fraunhofer lines are produced by absorption taking place in the 
chromosphere, while others are produced by absorption at higher levels. 
(19.) The eclipse work strengthens the view that chemical substances are dissociated 
at solar temperatures. 
I have finally to express my thanks to Messrs. Fowler and Shackleton, not only 
for the admirable manner in which they performed the duties entrusted to them in 
securing the photographic records of the eclipse spectra, as will be gathered by a 
perusal of their reports, but for assistance in the preparation of the present memoir. 
Mr. Fowler has generally assisted in the discussion of the photographs, and Mr. 
Shackleton is mainly responsible for the determination of wave-lengths. Messrs. 
Baxandall and Butler have also rendered assistance in various ways, and the 
photographic enlargements have been made by Corporal Haslam, It.E 
MDCCCXCVJ.-A. 4 T 
