The Catholic World, Vol. 10, October, 1869 to March, 1870

by Various

The plans for photographing the successive phases were most perfect. The movement of the sun from east to west of course made it necessary that the plate should also move correspondingly, but this was readily accomplished by connecting it with a telescope mounted on an axis parallel to the earth's equator, which axis is itself fixed to another at right angles to it, or parallel to that of the earth; this second axis being turned by clock-work once in twenty-four hours in a direction opposite to that of the earth's rotation, all the parts of the instrument evidently follow the movement of the heavens or of any celestial object to which the telescope may be directed. The axis around which the telescope turns can be rotated by hand or clamped in position, and in connection with the other, which can be disengaged from the clock-work, enables the instrument to be pointed in any direction at pleasure. This style of mounting is known as the equatorial, and is almost always used for astronomical telescopes. It is similar to the ordinary tripod used for small instruments, except in the addition of clock-work, and in having the principal axis inclined toward the pole-star instead of being vertical.

But it was necessary not only to take photographs, but to know the time at which they were taken, that they might accurately measure the movement of the lunar disc over that of the sun. This might have been secured by simply noting them from the face of the chronometer; but the object was more neatly and certainly attained by having the slide itself, as it dropped at the end of the exposure, break the electric circuit, and record its own time on the chronograph.

The spectroscopic work was the most difficult and important of all. Professor Winlock, the director of Harvard College Observatory and chief of the party, had charge of this. Though, as above stated, it has been found that the prominences can be seen with the spectroscope at any time, still the probability that they could be better observed at the time of the eclipse than at other times made it a duty to try the experiment, and the result has, as will soon be seen, proved that such is the case. Another observation was obtained with a spectroscope at Bardstown.

A large number of persons had come in, some from considerable distances, to observe the expected phenomenon. Among them was Mr. Frankenstein, of Springfield, Ohio, an artist, who hoped to paint the appearance of the eclipse and its effect on the landscape. This seemed an admirable idea, and it is quite remarkable that attempts of this kind have not been previously made; as they have not, at least to our knowledge. The circumstances of the present one made it eminently suitable for pictorial effect, owing to the small altitude of the sun; and the landscape, seen from the point selected, (some high hills east of the town,) is certainly one of great beauty.

The clouds broke away at about midnight and the thermometer fell considerably, reading about 59 at sunrise. The observing party improved the opportunity for final adjustments of instruments and preparatory observations, and hope revived in the hearts of all.

The sun rose unobscured on the morning of the 7th, and the day was cloudless till about ten o'clock, when some small cumuli drifted for about an hour across the sky, which then resumed its unbroken blue. The weather was also delightfully cool with a light breeze, which increased in the afternoon, and at four was blowing quite freshly. There were no signs of the predicted hailstorm, and strong faith would certainly have been needed for one to retain a belief of its arrival.

As the prospect of fine weather improved, and in fact seemed almost certain, the people, citizens and strangers, assembled on the observatory hill, and a rope was drawn round the tent where the instruments were mounted, to prevent a natural but dangerous curiosity on the part of those not immediately engaged in the special observations.

Every one now felt that they would be fully repaid for the time and labor devoted to the journey.

At about half-past four the edge of the sun was visibly indented; some persons maintained that they could see the moon some time previous to the contact; but this must probably be ascribed to a lively imagination. Smoked glass now came into demand, and all eyes were anxiously watching the rapidly decreasing orb. I had secured, through the kindness of an influential friend, an excellent position on the court-house, itself a high building and situated on the highest point in the town, commanding a fine view in all directions, particularly toward the north-west, from which quarter the shadow was sweeping toward us at the rate of more than a mile every second.

Some five or six gentlemen had followed me to the roof of the building, after which the ladder leading to the cupola was drawn up, to prevent a general ascent by the crowd below. At a quarter or twenty minutes past five, the wind began to abate, and the darkness was quite noticeable, and of course from that time continually increased, the general effect being like that of moonlight some time before the totality. The darkness was much more striking than at any time during the annular eclipse of 1854; this was probably owing to the total absence of any cloud, which would have reflected and multiplied the light of the unobscured portion of the sun, as on that occasion.