TOTAL ECLIPSE OF THE SUN, JANUAEY 22, 1898. 
173 
red part of the spectrum. Two of the chief questions on which such observations 
might he expected to throw light were (1) whether the green ring image of the 
corona corresponded with the outline of the corona ; (2) whether hydrogen was present 
or absent from the corona, as indicated by the presence or absence of a coronal 
ring at Ha. 
In addition to the visual observations, an experiment was made as to the 
efficiency for photographic work of a small camera fitted with a transmission grating. 
Senior Engineer Mountifield, E.N., who was in charge of this work, reports as 
follows ;— 
“ The instruments used in these observations were five in number, and consisted 
of (l) A direct-vision hand spectroscope-prism section only of about inch diameter, 
giving a spectrum of about 10° visual angle. 
“ (2) A ‘ meteor spectroscope ’ of about f inch diameter, giving a spectrum of 
about half the length of the first. 
“ (3) A prism with a refracting angle of 60°. 
“ (4) and (5) Prisms with refracting angle of 45°, 
“Instruction was given during the 14 days preceding that of the eclipse, the 
general nature of continuous and discontinuous spectra explained and illustrated 
by means of small, straight, and circidar slits in tinfoil placed before the flame of a 
spirit lamp, and observed through the instruments to he used. 
“ The probable variations iii the actual spectrum to be observed were also 
explained. 
“ The observers were instructed to note specially shapes which appeared to be 
repeated in different parts of the spectrum, and the number of parts in which they 
were repeated. 
“ The actual observations were commenced at 12.30, local mean time. Each 
observer was provided with an assistant, who noted down on a form, ruled in columns 
—one for each 10 seconds of totality—what was seen. 
“ At the commencement of observations, the greatest breadth of the sun’s 
crescent was about one-sixth of its diameter, and only a bright continuous s|)ectrum 
could be seen. 
“ My own observations were as follows:—At 12.33 the crescent had become so 
narrow that two curved dark lines appeared faintly in the red. 
“ Other lines soon appeared, and gradually increased in distinctness, until about 
12.43, when those in blue and green began to disappear, followed by yellow, green, 
orange, and red in the order named. No dark lines were distinguishable by me half 
a minute before totality. 
“ At the commencement of totality a number of bright arcs flashed out suddenly 
—the number could not be estimated reliably, but two arcs in red, one in yellow, 
one in greenish-yellow, one in green, and one in blue were noted. 
“ In from 1 to 1^ seconds these had faded, leaving a few irregular bright arcs. These 
