Professor C. S. Hastings, of the Johns Hopkins University, also includes many interesting details in his account of the trip:
The voyage from New York to Panama was pleasant with the exception of a few hot days near Aspinwall. Somewhat further south the wind changed, obliging them to call their overcoats from the bottom of their trunks to keep out the cold when crossing the equator. During a short stop in Lima the party had an opportunity of studying South American life. The products of this country are fruits and photographs of the young women. The party enjoyed both eating the former and bringing the latter home for the admiration of their friends. The expedition really began at Callao, where the party embarked on the United States man-of-war Hartford. Few circumstances contributed more to the enjoyment of the trip than the lucky chance which threw this vessel in their way. The Hartford was fitted out last August as flag ship of the South Pacific squadron. The admiral had not yet removed his flag to the vessel, but the extra accommodations provided for him and his train condoned the dignity lost by his absence. On March 22 they weighed anchor for a sail of more than four thousand miles over the blue ocean which stretches between Callao and their destination, Caroline Island. The southeast trade winds favored them, and from the first day there was actually no necessity for altering the position of a sail....
The inhabitants--five men, one woman and two children, according to the eclipse census--are natives of Tahiti. The houses are one story structures with clapboard sides, probably cut out in California and brought out in ships, to be erected on this island. The island on which they are built is about three-fourths of a mile in diameter and nearly circular in outline. The edge, which rises from five to twenty inches from the water, according to the tide's phase, goes down under the water to an even table of coral running out many feet into the sea; and is impossible to step on it with bare feet. At the end of this table the reef goes down perpendicularly, a sheer precipice, into the unfathomable sea. No vessel can anchor here, and to make a landing was an exciting matter. The island was approached in small boats on the side sheltered from the wind, and here, with the luck which characterized the trip, was found the only opening in this barrier of coral. A long cleft, perhaps eight feet wide, at the outer edge of the reef, ran in, narrowing to a mere crack near the shore. Watching a favorable chance, the boats were guided through the surf into a cleft as far as shoal water, when the men jumped on to the reef and carried baggage and instruments ashore as quickly as possible. The boats, which were new when they entered the surf, came out much the worse for wear, and the boat in which Dr. Hastings landed was stove in. Once on shore, life became a succession of wonders, rivaling the tales of Gulliver, and needing the conscientious descriptions of exact scientists to make them credible.
The members of the observing party took up their abode in the larger of the three houses, sleeping in swinging cots slung from the verandas, which afforded shade on three sides of the building. The second house was occupied by the sailors, while the third was left to the natives. These latter were sufficiently conversant with English to serve as excellent guides. Each day the party bathed in a lagoon in the center of the island. This lagoon was bordered by a beach of dazzling white coral sand, and all through its water extended reefs of living coral of the more delicate and elaborate kinds. These corals gave the lake a wonderful variety of colors, forming a picture impossible to paint or describe, and with the least ripple from a passing breeze the whole scene changed to new groups of color. The water was very clear, and in some places deep; in others so filled with coral that a boat could barely skim over the surface without scraping the keel. After crossing a long reef, one day, they entered on a sheet of water so deep that their longest line would not reach the bottom, plainly visible beneath. Fish swarmed here, and it was characteristic of them that every species, if not brilliantly colored, was marked in the most peculiar manner. One variety which frequented the shallow water, where it was heated to the degree uncomfortable to the touch, was a pure milky white, with black eyes, fins, and tail.
The French party arrived two days after the Americans. They had steamed directly from Panama with the hope of anticipating the Americans.
It rained on the morning of the eclipse, but cleared off in good time, and the definition was particularly good. Photographs occupied the time of the English and French observers. Professor Holden and Dr. Dickson searched for intra-mercurial planets; Mr. Preston took the times of contact; Dr. Hastings and Mr. Rockwell devoted their attention to spectroscopic observations of the corona. Dr. Hastings' observations have led to the production of a new theory of the corona. Briefly stated, the theory is that the light seen around the sun during a total eclipse is not due to a material substance enveloping the sun, but is a phenomenon of diffraction.
From his observation during the eclipse of 1878, made at Central City, Dr. Hastings conceived the first idea of this explanation of the solar corona. Further study served to convince him of the truth of this theory, but he had no means of proving it. Before the present eclipse, however, he devised a crucial test of his theory. This test is based on the following already known phenomena: When the moon covers the face of the sun, an envelope of light is seen all round it; the envelope is not visible when the sun is shining, on account of the sun's greater brightness; this light is called the corona; it is extremely irregular in outline. According to the drawing of Mr. J. E. Keeler at the eclipse of 1878, it enveloped the sun as a hazy glow, extending for a distance of several minutes of arc from the sun's limb and at two nearly opposite points is extended out in two long streamers feathering off into space. The opinion has been that this light was due to an atmosphere extending millions of miles from the sun. According to Dr. Hastings' view, it must be light from the sun which has undergone refraction, i.e., which has been bent from its regular course by the interposition of an opaque body like the moon.
In order to make this perfectly plain, suppose the front of a surface of waves of any sort to be striking an object which resists them. If an organ of sense is placed in the resisting object, it will judge the direction of the waves or the direction of the object producing them by a line at right angles with the wave front. Now suppose a body is placed between the body producing the waves and the sensitive organ. The waves must go around this body and will produce an eddy behind it, so that the wave front will have a different direction, and the organ of sense will conceive the origin of the waves to lie in a direction different from that before the body was interposed. Now consider the waves to be waves of light, and their origin the sun. The organ of sense is the retina of the eye. The moon is the opaque body interposed in the course of the waves, and they, being bent, make the impression on the eye that the light comes from beyond the edge of the sun. The moon covers the sun during the eclipse and a little more, so that it can move for about five minutes and still cover the sun entirely. This movement is very slight, and if the corona consists of light from a solar atmosphere, it should not change at all during this movement of the moon. But if diffraction is the cause of the light, then the slightest change in the relative positions of the sun and the moon should change the configuration of the corona, i.e., the corona should not remain exactly the same during a total eclipse. The character of the light as shown by a spectrum analysis should change.
To determine this point Dr. Hastings invented the following instrument: Two lozenge-shaped prisms of glass were fastened in the form of a letter V, and so arranged that all the light falling within the aperture of the V was lost, and that falling on the ends of the glass prisms was transmitted by a series of reflections to the apex of the V, where the prisms touched; here was placed a refracting prism, so that the light could be analyzed. This instrument was attached to the eye piece of the telescope, and the image of the eclipse reduced to such a size that the moon just fitted into the aperture of the V, while opposite sides of the corona were reflected through the prisms to the place where they came together. In this way both sides of the corona were seen through the eye-piece at the same time. On looking at the eclipse this is what Dr. Hastings saw: The light of the corona was divided into its constituents. Prominent among them was a bright green line, which is designated by the number 1,474; to this line attention was directed. Its presence in the spectrum has been an argument in favor of the view that the corona is a solar atmosphere. If this is the case, the line should remain fixed during the eclipse; but if the corona is due to diffraction, this line should change. It should grow shorter in the light from one side of the corona, and longer on the other. The observation was now reduced to watching for a change in the relative length of two green lines.
At the beginning of totality the line from the west side was much the longer, but as the eclipse progressed it shortened notably, while the line from the east side, shorter by about one-third at the beginning of the eclipse, grew longer. When the eclipse ended, the proportions of the lines were exactly reversed. There had been a change equal to two-thirds the length of the lines, while the sun and moon had only changed their relative positions by an extremely small amount. The only way in which this phenomenon can be accounted for is on the diffraction theory. The material view of the corona will not answer for it. But there are other discrepancies in the older view which have been known for some time. The principal ones are: 1. It is known from study of the sun that the gaseous pressure at the surface must be less than an inch of mercury, and is probably less than one-tenth of an inch, but an atmosphere extending to the supposed limits would cause an enormous pressure at the sun's surface, especially since the force of gravity on the sun is very much greater than on the earth. 2. The laws of gravitation would require a solar atmosphere to be distributed symmetrically around the sun, while the corona is enormously irregular in form. The sun is irregular in outline, which would make its diffracted phenomena show the observed irregularity, but it is symmetrical as regards density. 3. The most interesting discrepancy of the theory of the solar atmosphere is the fact that while it is supposed to extend for millions of miles from the sun, the recent comet passed within two hundred thousand miles of the sun, and yet its orbit was not affected in the least, as it would have been if it had plowed its way through a material substance. In taking photographs of the corona it is seen to be larger as the time of exposure is longer. This shows that the corona extends indefinitely, and it decreases in brilliancy in exact accordance with the mathematical laws of diffraction. These laws involve very complicated mathematics, but by them alone Dr. Hastings has proved that there must be diffraction where the corona is, and that it must follow the same laws as those observed. There is a small envelope around the sun, but in the opinion of Dr. Hastings it does not extend beyond what is known as the chromosphere.