nced, through
changes in the coronal spectrum at epochs of sun-spot maximum.

The prosperous result of the Sohag observations stimulated the desire to
repeat them on the first favourable opportunity. This offered itself one
year later, May 6, 1883, yet not without the drawbacks incident to
terrestrial conditions. The eclipse promised was of rare length, giving
no less than five minutes and twenty-three seconds of total obscurity,
but its path was almost exclusively a "water-track." It touched land
only on the outskirts of the Marquesas group in the Southern Pacific,
and presented, as the one available foothold for observers, a coral reef
named Caroline Island, seven and a half miles long by one and a half
wide, unknown previously to 1874, and visited only for the sake of its
stores of guano. Seldom has a more striking proof been given of the
vividness of human curiosity as to the condition of the worlds outside
our own, than in the assemblage of a group of distinguished men from the
chief centres of civilisation, on a barren ridge, isolated in a vast and
tempestuous ocean, at a distance, in many cases, of 11,000 miles and
upwards from the ordinary scene of their labours. And all these
sacrifices--the cost and care of preparation, the transport and
readjustment of delicate instruments, the contrivance of new and more
subtle means of investigating phenomena--on the precarious chance of a
clear sky during one particular five minutes! The event, though
fortunate, emphasised the hazard of the venture. The observation of the
eclipse was made possible only by the happy accident of a serene
interval between two storms.

The American expedition was led by Professor Edward S. Holden, and to it
were courteously permitted to be attached Messrs. Lawrance and Woods,
photographers, sent out by the Royal Society of London. M. Janssen was
chief of the French Academy mission; he was accompanied from Meudon by
Trouvelot, and joined from Vienna by Palisa, and from Rome by Tacchini.
A large share of the work done was directed to assuring or negativing
previous results. The circumstances of an eclipse favour illusion. A
single observation by a single observer, made under unfamiliar
conditions, and at a moment of peculiar excitement, can scarcely be
regarded as offering more than a suggestion for future inquiry. But
incredulity may be carried too far. Janssen, for instance, felt
compelled, by the survival of unwise doubts, to devote some of