SCIENTIFIC SUMMARY. 
42 S 
"but under conditions which promise better success than has hitherto been 
obtained. In particular, advantage is to be taken of the experience acquired 
by Mr. Brothers last year. Mr. Brothers, it may be remembered, adopted a 
new method of photographing the corona, making use of an ordinary 
photographic lens of long focus instead of a telescope. Notwithstanding very- 
unfavourable weather, the eclipsed sun having been clouded over until within 
a few seconds of the end of totality, Mr. Brothers succeeded, as we know, in 
picturing the corona “ as it was never seen on glass before.” It is not to be 
wondered at, therefore, that it has been decided to employ the same method 
on the present occasion. The proposed spectroscopic observations are also 
promising. Two excellent 6-inch refractors are to be mounted on the same 
equatorial stand, one at each end of the declination axis ; so that, while 
one observer studies the aspect of a portion of the corona through one tele- 
scope, another may study the spectrum of the same portion through the 
other. This contrivance has been suggested by Dr. Huggins, and appears 
well calculated to remove the doubts which have hitherto rested on the 
subject of those spectroscopic observations which have been guided merely 
by means of the ordinary finder. Mr. Lockyer has made suggestions, among 
which the following may be noticed. “ At each place,” he says (i.e. India, 
Ceylon, and Australia), “ the spectroscopes should be employed for half-an- 
hour (to be on the safe side) before totality, in scrutinising the crescent at 
its narrowest place, and the chromatosphere outside the following limb of 
the moon. At each place, as before defined, there should be a spectroscope 
with a finder and equatorial motion (or some equivalent arrangement) 
directed to the sun’s centre, to record any changes which take place in the 
spectrum from, say, half-an-hour before to half-an-hour after totality, and 
also during totality, bien entendu. The relative darkness or brightness of the 
lines should be recorded every ten seconds. The spectroscope should have 
moderate dispersion, large object-glasses for collimator and telescope, and with 
focal length such that two or three degrees round the sun should be take i 
in (i.e. 1° or 1^° from the sun’s centre), and a large field.”. . . 
Coming to the details of the expedition to Ceylon, Mr. Lockyer expresses 
the opinion that it need not exceed the following numbers : — 
1 telescope-spectroscopic observer ; 2 assistants. 
1 photographer; 2 assistants.* 
1 spectroscopic observer ; 1 assistant. 
Or 8 in all. 
To one suggestion of Mr. Lockyer’s we are compelled to take grave ex- 
ception. He notes, among observations which he regards as comparatively 
unimportant, 11 sketching anything but the changes in the corona.” It appears 
to us, on the contrary, that the changes in the corona are precisely the 
phenomena which are, in the first place, most difficult to delineate ; and, in 
* Mr. Lockyer remarks that, in his opinion, this duty may perhaps be 
entrusted to skilled sappers. But the history of all the recent eclipses shows 
that, of all the departments, the photographic is the one which requires to 
be entrusted to the most skilful hands. Very useful spectroscopic work has 
been done with very little preceding practice ; but no good photographic work 
has yet been done save by experts. 
