world devoted to solar research is the Carnegie Solar Observatory on Mt. Wilson in California. There, under the direction of Dr. George E. Hale, many startling revelations regarding the central luminary of our system have been made. The dark lines in the spectrum of the sun are caused by the absorption of light from the white-hot body of the sun as it passes through the cooler layers of atmosphere encircling the sun itself. But these layers of atmosphere are cool only in contrast with the much hotter sun. The gases are in fact very hot, and would give their spectra of bright lines if the still brighter background of the sun could be cut off. At eclipse time the moon comes between us and the sun. As long as there is only a small portion of the sun visible, its light is so intense that the spectroscope gives the ordinary solar spectrum. At the instant that the moon entirely covers up the surface of the sun, the solar spectrum suddenly changes from a spectrum of dark lines on a bright background to bright lines on a dark background. The change is so sudden that Young, of Princeton, who first saw it at the eclipse of 1870, named it the "flash spectrum." This flash spectrum lasts for the brief space of about three seconds of time at the beginning of the total phase, and again at the end. It was not until 1893 that the first photograph was obtained of the flash spectrum. At each succeeding eclipse, the photography of this spectrum has been, perhaps, the most important problem to be attacked. The eclipse of 1905, visible in Spain, gave the most perfect photographs of this phenomenon yet obtained. These photographs furnish us with much information of value regarding the physical constitution of the atmosphere of the sun, the height in miles to which these various gases extend above the surface of the sun, and other details of similar character. It may almost be said that we have more

accurate information as to the constitution of the atmosphere of the sun nearly ninety-three million miles away than we have of our own terrestrial atmosphere ten miles above our heads.

The spectroscopic work of the Naval Observatory party for 1918 was planned in the hope of surpassing even the excellence of the photographs of 1905, but mainly with the intention of extending our spectroscopic knowledge much farther toward the red end of the spectrum than had been accomplished by other eclipse observers. Three separate instruments were used, each consisting of a Roland concave grating. The scientists engaged in the spectroscopic program were Dr. P. W. Merrill, of the Bureau of Standards of Washington; Dr. Harriet W. Bigelow and Dr. Mary Murray Hopkins, both of Smith College; and Dr. L. G. Hoxton and Dr. S. A. Mitchell, of the University of Virginia.

Fortunately for the work of preparation, no rain fell during the entire stay of the astronomical party in Baker. According to the "oldest inhabitant," the season was unusually dry even for eastern Oregon. By some mysterious force unknown to the astronomers, the eclipse seemed to exert some potent influence over the weather. At any rate, it was asserted by many of the rural papers that no rain could be expected until the eclipse was over. But if there was an absence of rain, there was no lack of clouds nor were the clear skies we had been led to expect afforded us. As the time for the eclipse drew nearer, the continued appearance of clouds began to cause anxiety among us. Would they interfere with the eclipse, and, at the last, make all the weeks of careful preparation of no account? If this had happened, it would not have been the first event of the kind. Unfortunately for the astronomer, his work is always at the mercy of the clouds and the weather. But to have the whole work

fail through the presence of clouds at the time of the few precious minutes of the total eclipse-that is indeed the keenest sort of disappointment! Some astronomers seem to be always unlucky and always experience cloudy weather on their eclipse expeditions, while, on the other hand, others are always lucky, and sometimes, after all hope is abandoned, a rift will appear in the clouds and the eclipse at totality be seen in all its glory. Would we at Baker be lucky or unlucky, would the clouds interfere or not? Nearly all the days spent in Baker, according to the classification of the United States Weather Bureau, were clear. But a "clear" day does not mean one when there is an entire absence of clouds. In fact, clouds gathered almost every day shortly after noon, and this condition was usually accompanied by very high winds, that at times rose to the strength of a mild gale. The eclipse was to occur during the middle of the afternoon, and at this time of day the skies were usually overcast. These same conditions prevailed over the whole of the western United States along the path where the astronomers were located. It was well to be an optimist under such conditions of sky, for the pessimist became more and more wretched as the day of the eclipse drew near and his law of averages showed him the almost certain chance of a thinly clouded sky during the total eclipse.

The writer of this article had so far been among the lucky astronomers. In 1900, at the first eclipse observed, the weather was ideal, not a single cloud in the whole sky. In 1901, he was a member of a rather large party which traveled halfway round the world. Only four of a total of thirteen saw the eclipse, the other nine witnessed the eclipse eclipsed by clouds. The writer was one of the fortunate four. Again in 1905, there were many clouds which spoiled the researches of many parties. At Daroca in Spain, a few minutes be

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fore totality a dense cloud covered the sun, but it cleared away before the allimportant time, and the total phase was seen through a brilliantly clear sky. Three lucky chances out of three made a fine average. The hope was that

June 8 would make it four out of four.

By May 30, the whole party had assembled in Baker. A full week was given up to the final adjustments, and to the drills that were to play such an essential part in the work on eclipse day. During the partial phases of the eclipse, very few observations of importance were to be made; all observations of value came during the period of totality which lasted for one hundred and twelve brief seconds. If a slide of a plate holder should stick in place so that it could not be removed, or a lens were not uncapped at the proper time so as to let in the light, the whole work of an instrument might come to naught. On each day of the week preceding June 8, drills were gone through several times in the morning and again in the afternoon. These drills were so well carried out that on eclipse day each and every one performed excellently the task allotted to him with the result that everything passed off without a single hitch.

As the days in June progressed toward the eighth, there was an air of excitement as each astronomer grew more keyed up to the task before him. Would the day be clear? But more especially, would the two minutes from 4:04 P.M. to 4:06 be clear on Saturday? The skies were anxiously watched during the last days, and almost every day the skies were overcast. The optimist reasoned that if it were cloudy all the days before June 8, then on eclipse day perfect weather would surely be forthcoming; while the pessimist reasoned that so many cloudy days meant still one more of the same character, so there was no use trying to do anything.

Saturday, June 8, dawned with the

sky overcast with thin, filmy clouds. The sun was well visible through these clouds, however, and it was possible to examine again the focus that had been obtained with the spectroscopes and with a touch here and a touch there to decide that everything was in perfect condition. During the morning the drills were again gone through with, and these seemed to promise success. The weather during the six weeks had not held up the work, and everything seemed now to have been done that thought and work could do. The astronomers who had been on the ground for the whole six weeks of preparation had the pleasant consciousness that all of their allotted tasks had been completed, that every little detail had been thought of, and that perfect success would certainly crown their efforts if the clouds

would only clear away. But during the course of the morning the clouds grew thicker instead of thinner, and it did indeed seem as if there were little chance of clear skies.

The first contact was to take place at 2:36 P.M. Shortly after noon the city of Baker took upon itself the aspect of a holiday. Though the day was Saturday, all stores were closed from three until five in the afternoon so that everybody could have a chance to see the phenomenon. Naturally everyone in Baker wished to go to the eclipse site at the Fair Grounds to watch the astronomers at work. At the eclipse in Spain, this had been permitted with the result that the whole town was assembled, each inhabitant jostling his neighbor to get as close as possible. Unfortunately, each Spaniard seemed

to be bent on telling his friend just what was being done, with the result that such a din arose when the eclipse became total that it was impossible to hear the seconds counted off to give warning to the astronomers when to change their plate holders.

That this might not happen again, the residents of Baker were told that the gates of the Fair Grounds would be closed, and absolutely no one would be admitted within the enclosure. The mayor of the city sent a guard of Boy Scouts to see that these orders were obeyed. Most of the town repaired to the hills to the southeast of the city

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from which there could be obtained a fine view of the valley and the Elkhorn Range, and they were directed to look especially for the shadow of the moon which would come across the landscape at the speed of about thirty miles a minute or 1800 miles an hour. This shadow comes with the advent of totality, and all who have seen the phenomenon say that it is an awe-inspiring spectacle, making one feel that the end of the world is surely at hand.

No appreciable improvement in the skies was observed from noon to the time of first contact. Through a thin patch in the clouds, Mr. Hammond,

using the five-inch visual telescope, observed the beginning of the eclipse and made a record of it. The clouds, if anything, became thicker after this so that at three o'clock it was impossible to see even where the sun was. Little thin rifts appeared at times, so that with the aid of smoked glass it was possible to see the moon encroaching on the face of the sun. At three thirty, a patch of brilliantly blue sky was seen off to the northwest, and as the precious minutes dragged along it became evident that the clouds were moving in such a way that it was quite possible that the blue patch would reach the sun in time for totality. Fifteen minutes before the total phase, the clouds were so dense that had totality occurred then, the scientific results would have

been nothing; but the blue sky was coming nearer and it might arrive in time.

Without looking at the sky, one realized that something unusual was happening. The light of the sun became so feeble that even the birds felt the unnatural aspect of things and sang their songs as if they were going to rest. The cocks crowed on the farm near by. The wind which was ordinarily blowing at this hour was quiet. All nature was hushed. Even the seasoned astronomers who had seen two or three eclipses before felt the thrill of the unusual spectacle. spectacle. And still the question was, Would the clouds clear away in time?

At five minutes before totality the warning signal was given by Chief Petty Officer Welsch of the United