Excerpt taken from Tumultuous Times:
"The last formal working day of the [First Vatican} Council was July 16, 1870, just two days before the solemn promulgation of Pastor Aeternus. An eyewitness described the dramatic scene at St. Peter’s Basilica on the remarkable day of the final vote:
"The fateful day of the Public Session, Monday, July 18, dawned in rain, after a night of thunder and lightning. St. Peter’s was opened at 7:30 and the Session began at 9. The crowd was not such as had filled St. Peter’s to overflowing at the opening Session, December 8: the July heat had dispersed the visitors. The only royalty present was the Infanta of Portugal. A votive Mass of the Holy Ghost was celebrated ‘sine cantu’ by a cardinal. Then the pope entered and assumed pontifical vestments, the Litany of the Saints was chanted, followed by the hymn ‘Veni Creator Spiritus’, intoned by the pope. A bishop approached the throne and received from the pope the Constitution ‘Pastor Aeternus’, and mounting the ambo read it through in a loud and clear voice. Then he put the question: ‘Right Reverend Fathers, do the decrees and canons contained in this Constitution please you?’ And the voting by ‘placet’ or ‘non placet’ began. It was carried through under circumstances of unforeseen impressiveness.
The storm, which had been threatening all the morning, burst now with the utmost violence, and to many a superstitious mind might have conveyed the idea that it was an expression of divine wrath, as ‘no doubt it will be interpreted by the numbers’, said one officer of the Palatine Guard. And so the ‘placets’ of the Fathers struggled through the storm, while the thunder pealed above and the lightning flashed in at every window and down through the dome and every smaller cupola, dividing if not absorbing the attention of the crowd. ‘Placet’, shouted his Eminence or his Grace, and a loud clap of thunder followed in response, and then the lightning darted about the baldacchino and every part of the church and the conciliar hall, as if announcing the response. So it continued for nearly one hour and a half, during which time the roll was being called, and a more effective scene I have never witnessed. Had all the decorators and all the getters-up of ceremonies in Rome been employed, nothing approaching to the solemn splendor of that storm could have been prepared, and never will those who saw it and felt it forget the promulgation of the Constitution of the Church.
The storm was at its height when the result of the voting was taken up to the pope, and the darkness was so thick that a huge taper was necessarily brought and placed by his side as he read the words ‘Nosque, sacro approbante Concilio, ilia, ut lecta sunt, definimus et apostolica auctoritate confirmamus.’ And again the lightning flickered around the hall, and the thunder pealed. The ‘Te Deum’ and their Benediction followed; the entire crowd fell on their knees, and the pope blessed them in those clear sweet tones distinguishable among a thousand.
“The great Session is over. The decree was voted by 533 ‘placets’ to 2 ‘non placets’ amidst the great storm The lightning flashed into the aula, the thunder rolled over the roof, and glass was broken by the tempest in a window nearly over the pontifical throne and came rattling down. After the votes were given the pope confirmed it at once, and immediately there was a great cheering and clapping from the bishops, and cheers in the body of St. Peter’s. Then the ‘Te Deum’ began, the thunder forming the diapason.”
...The two bishops who voted against the decree of papal infallibility were Edward Fitzgerald of Little Rock, Arkansas and Luigi Riccio of Cajazzo, Italy. However, both men subsequently offered their humble obedience to the pope and their submission to the formal decree of the council. The Franco-Prussian War broke out the following day."
– Dom Cuthbert Butler, 'The Vatican Council 1869-1870' and 'Vatican Council: The Story Told from Inside, Vol. II' cited by the Fathers Radecki in 'Tumultuous Times'.
