CLEAR FOR ACTION.
However, Saturday came at last, and the morning was hazy and overcast; but about eight, the clouds began to break and Mr. Vail and I took some observations for “time.” The afternoon was cloudless; but still a haze near the horizon. At half-past three, we “Beat to quarters.” Mr. Douglas shut himself up in the dark room; I took charge of the telescope; Mr. Stanton, with a light cloth, covered and uncovered the “object glass;” Mr. Vail had his telescope nicely adjusted; and Mr. Falconer was seated in a very good position to observe the dark shadow crossing the country, and to note any other phenomena. At 3h. 38m. 40s., local mean time, the first contact took place, and the first photogram taken, shewing a slight indentation on the sun’s limb. We took the partial eclipse with an eye-piece, giving a 3-inch picture but as it was hazy, I removed it before totality, and took the photograms in the principal focus.
I may remark that no one could have had a better view of the eclipse than I had. As I stood in rear of the telescope, I had only to count the double beats of the pendulum of the “Driving Clock,” which I did without taking my eyes off the moon.
I exposed the plates of totality for ten seconds, then withdrew the holder, and handed it to Mr. Douglas. We took several photograms of the partial eclipse before totality, four during totality, and two after; but the weather had become so hazy, immediately after the sun made its appearance, that we could hardly get a picture. As all the reports are published, it only remains for the Jefferson party to give theirs, and the eclipse of 1869 can be fully discussed. There are one or two points that the negatives of our party will throw a light upon.
With regard to the bright band on the sun, bordering the moon, in the pictures of the partial eclipse, it is well known that, there is nothing surrounding the moon that could produce that effect; and also, that the photograms taken at Burlington, shew, beyond a doubt, that it is no optical illusion. Dr. Curtis has suggested that it is caused by diffraction; still, I very much doubt if diffraction could produce such a uniform dark broad band, so well defined, as is seen in those photograms. One of the photograms of the partial eclipse that we took before totality, shews the cusps and edge of the moon to be double, giving the appearance of a band surrounding the moon. This is caused by the reflection of the moon from the second or underside of the glass, which happens when the sun is not in the centre of the field; and by holding the negative of a partial eclipse so that the light will fall obliquely on it, you will see a dark band surrounding the moon’s limb, from the same cause.
“bailey’s beads.”
In the eclipse of 1860, I had the honor of being attached to the American Expedition that went to the coast of Labrador. Professor Alexander, Dr. F. A. Barnard and myself, who were observing with telescopes, all exclaimed at the same time, “Bailey’s Beads!” It is very true, that at Otumwa a picture at the last instant, just before totality, was taken, “shewing the sun’s edge cut by the peaks of the lunar mountains into irregular spots;” but these were not the Bailey Beads that I saw in Labrador, and I am confident that neither Professor Alexander nor Dr. Barnard will accept that solution. In the report of Mr. W. S. Gilman, junr., who observed the eclipse at Sioux city, Mr. Farrel gives a description and drawing of Bailey’s Beads; and what he saw in 1869, I saw in 1860, the film of light broken into rectangular pieces, which appeared to swim along the edge of the moon like drops of water.
A crowd had followed us from the town, and took a position near the observatory, as, no doubt, they thought that we would select the best place for observing the eclipse.