THE GREAT ECLIPSE OF AUGUST 17, 1868. 
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during which to observe the phenomena which are presented 
during total eclipse. It is also obvious that, in the middle of 
the totality, the obscurity will be far greater than in the eclipse 
of 1860, since the extent by which the moon’s disc extends 
beyond that of the sun will be nearly twice as great. We may, 
therefore, hope that important information will be derived 
from the observation of this great eclipse, respecting the inter 
esting phenomena which attend the total obscuration of the sun; 
and, in particular, it is to be hoped that something will be 
learned respecting the nature of those coloured prominences 
and floating masses which become visible round the moon’s disc. 
It is possible that changes which may be in progress in the 
figure or position of the prominences may be detected by a 
comparison of views taken by different observers ; since a con- 
siderable interval will elapse between the passage of the shadow 
over the western and eastern parts of the Indian peninsula. 
It is satisfactory to learn that two expeditions, well provided 
with instruments, have proceeded to India from England for the 
purpose of observing the great eclipse. 
The first, organised by Major Tennant, has been sent out 
under the auspices of the Eoyal Astronomical Society. “ An 
application was made to the India Office, to bear the expense of 
establishment and instrumental means.” For photography, a 
silvered glass reflector has been provided. Three men of the 
Eoyal Engineers have been trained at Mr. Delarue’s Observa- 
tory at Cranford, in the processes of taking small negatives, 
enlarging, and etching them on glass. The reflector, of 
inches diameter, is a Newtonian, and is mounted equatorially 
and driven by clockwork. Mr. Browning has devoted much 
time and care to the construction of this instrument, and has 
been assisted by Mr. Delarue’s advice and experience ; in other 
words, all that science and skill could devise to render the 
instrument perfect has been applied to its construction. A 
telescope belonging to the Astronomical Society has been 
provided for spectroscopic researches, and one of the Greenwich 
telescopes has been adapted to the polarization apparatus. 
The second expedition has been sent out by the Eoyal 
Society under Lieutenant John Herschel, a son of Sir John 
Herschel. Lieutenant Herschel has received instructions to 
confine his attention to observations of the spectra of the corona 
and red prominences.” He is provided with an equatorial 
telescope, five inches in aperture, for spectrum observations. 
Another telescope, three inches in aperture, has been provided 
for observations for polarized light. Lastly, “ four hand spec- 
trum-telescopes, of the form constructed by Mr. Huggins for the 
observation of meteors, have been sent for use by observers 
stationed at different places along the central line of the eclipse.” 
