
NATURE 

THURSDAY, JULY 13, 1871 


THE NEXT TOTAL SOLAR ECLIPSE 
T is infinitely to the credit of English men of science 
that they are at the present moment busily engiged 
inmaking arrangements for observations of the Total Solar 
Eclipse in December next, and it is extremely fortunate 
for the advance of Science that this rare phenomenon— 
rare, that is, so far as the chance of observing it with 
moderate facility goes—occurs again just as the know- 
ledge gleaned by the recent expeditions is being garnered 
to serve as a Starting point for future inquiry. 
When we state that the eclipse will be visible as a total 
one in India, Ceylon, and Australia, it may at first be 
imagined that in this case the facilities are not so very 
great. This would be quite true if it were necessary to 
garrison all these stations with observers from England ; 
but, as it happens, the Governments both of India and 
Victoria have under their orders government astronomers 
—Mr. Pogson at Madras, and Mr. Ellery at Melbourne ; 
and all that is necessary is to forward to those stations 
instructions, so that the observers there may glean 
all the experience gained in the last eclipse, and instru- 
ments such as are required to advance our present know- 
ledge. And here we may remark that our knowledge in 
solar matters has recently advanced so rapidly, that astro- 
nomers have, as it were, to use new weapons in each attack, 
as artillery gives place to small arms, and small arms to 
the bayonet, in less scientific warfare. 
That India and Australia will thus be provided with 
everything that may be necessary will be evident when 
we state that the Astronomer Royal is superintending the 
adaptation of instruments already in his possession for 
use in the former country, while the President of the 
Royal Society has already communicated with the autho- 
rities in Australia, offering to aid in every way in the pro- 
posed observations—an offer which we doubt not will be 
accepted, and in both cases we may hope for results of the 
highest importance, if the local observers set to work with 
a will. As to the entire sympathy of both governments 
there can be no question, India was magnificently help- 
ful to Janssen in 1868, and Australia has her spurs to win ; 
and there are good men in plenty, in both places, in whom 
the Governments may place their fullest confidence. 
There remains, then, Ceylon. Both the Royal and 
Royal Astronomical Societies have determined, if the 
Government will help, to send out a small party of ob- 
servers from England to garrison this mid-station, which 
modern helps to travel have placed at our doors, and who 
knows that at one station or other Americans and French- 
men may not be found to join inthe good work? The 
new railway has made an American Expedition extremely 
easy. 
And now let us enter a little more into particulars. 
The central line of the eclipse will first meet the earth’s 
surface in the Arabian Sea, and entering on the western 
coast of India, will pass right across one of the most im- 
portant parts of Hindustan, in a S.E. by E. direction. In 
this part of the peninsula the sun will be about 20° above 
the horizon when totally obscured. The duration of totality 
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197 

will be two minutes and a quarter, and the breadth of the 
shadow about seventy miles. On leaving the eastern coast 
of the Madras Presidency, the central line will cross Palk’s 
Straits, passing about ten miles S.W. of the island Jaffna- 
patam, and over the northern part of Ceylon, where the 
small towns of Moeletivoe and Kokelay will lie near the 
central line ; and also the well-known naval station of 
Trincomalee, which will be about fifteen miles S.W. of the 
line. Continuing its course over the Bay of Bengal, the 
shadow will cross the S.E. point of Sumatra, and will 
touch the south-western coast of Java, where Batavia, the 
capital, will lie nearly sixty miles N.E. of the central 
line ; and two other smaller towns, Chidamar and Nagara, 
will also be very near the middle of the shadow path, In 
the Admiralty Gulf, on the N.W. coast of Australia, the 
eclipsed sun will be only ten degrees past the meridian, 
and not far from the zenith ; in consequence of which the 
totality will last 4™ 18°, or only four seconds less than the 
time of greatest duration. Lastly, passing through the 
most barren and uninhabited portion of Australia, crossing 
the Gulf of Carpentaria and the York Peninsula, the 
shadow will ultimately leave the earth’s surface in the 
Pacific Ocean. 
At present not too much is known about the chances of 
weather at any place ; but what is known seems to point 
to a fair chance of success in both India and Ceylon, as 
the eclipse occurs during the N.E. monsoon ; but, in any 
case, the experiences of the last Expedition show that 
for such a momentary phenomenon these chances need 
scarcely be taken too seriously into consideration, see- 
ing that where the finest weather was predicted a terrible 
pall of cloud covered the sky. 
Next as to the work which the present state of our 
knowledge shows to be most desirable. This has been 
pointed out by Mr. Lockyer, in a communication to the 
Royal Society, and here we may in the main quote from 
his paper. Mr. Lockyer states :— 
“Tn my opinion the fundamental points of attack are : 
“a. Spectroscopic observations made with such 
an instrument as the one I took out to Sicily, 
eguatorially mounted, and with reference spectra. 
‘““8, Photographic observations made with such 
an instrument as the one I took out to Sicily, namely, 
a camera with large aperture and small focal 
length eguatorially mounted. 
“Perhaps I may clear the ground by stating what, in 
my opinion is comparatively UNIMPORTANT, So far as the 
crucial points are concerned, though to be tolerated if the 
crucial points are strongly taken up. 
“aq. Photographing prominences, 
“8B. Sketching anything but the changes in the 
corona. 
‘“‘y, Polariscopic observations. 
“§ Observing Baily’s Beads. 
There should be one instrument, and Mr. Pogson 
could probably provide this in India, to determine the 
position of prominences before and after totality. During 
totality they should not be observed at all except inci- 
dentally. 
“At each place (z.2., India, Ceylon, Australia) the spec- 
troscopes 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 chromosphere outside the 
following limb of the moon. 
“ At each place, as before defined, there should be a 
spectroscope with a finder, and equatorial motion 
M 
