CHAPTER IV
FIREBALLS
Here we penetrate into what is, perhaps, the most mysterious, and certainly the least understood domain of thunder and lightning.
Among all the electrical phenomena to be observed in the atmosphere, there is nothing stranger than those fireballs of which we have already spoken, and which in form and size recall the electric lights in our Paris boulevards. Curious the contrast between electricity tamed and civilized and electricity running wild! Between the arc lights fulfilling their peaceful and useful function as substitutes for the sun, and these dread engines of destruction sowing death and havoc!
It is not long since the existence of these fireballs has been acknowledged by scientists as an actual fact. Until quite recent times they were regarded as the figment of excited imaginations, and wise men smiled at the wild stories of their ravages. Their reality has now been established, however, beyond the possibility of doubt.
In shape they are not always quite spherical, though this is their normal appearance; and although their contours are usually clearly defined, they are sometimes encircled by a kind of luminous vapour, such as we often see encircling the moon. Sometimes they are furnished with a red flame like a fuse that has been lit. Sometimes their course is simply that of a falling star. Sometimes they leave behind them a luminous trail which remains visible long after they themselves have disappeared. They have been described as looking like a crouching kitten, an iron bar, a large orange—so harmless apparently, that you were tempted to put out your hand to catch it. There is record of one being seen as large as a millstone.
One remarkable thing about them is the slowness with which they move, and which sometimes enables their course to be watched for several minutes. In our first chapter we gave several instances of the occurrence of fireballs. Let us look at some more. Here is one taken from Arago's learned treatise upon thunder. The record is from the pen of Batti, a marine painter in the service of the Empress of Austria and resident at Milan.
"In the month of June, 1841, I was staying at the Hôtel de l'Agnello in a room on the second floor, overlooking the Corso dei Servi. It was about six in the afternoon. The rain was coming down in torrents, and the darkest rooms were lit up by the lightning flashes better than our rooms generally are by gas. Thunder broke out every now and again with appalling violence. The windows of the houses were closed, and the streets were deserted, for, as I have said, there was a steady downpour, and the main road was turned into a torrent. I was sitting quietly smoking, and looking out at the rain, which an occasional ray of sunlight set flashing like threads of gold, when I suddenly heard voices in the street calling out 'Guarda, guarda!'—'Look, look!' and at the same moment a clatter of hob-nailed boots. After half an hour of absolute silence, this noise attracted my attention. I ran to the window, and looking to the right, in the direction of the clamour, I saw a fireball making its way down the middle of the road on a level with my window, in a noticeably oblique direction, not horizontally. Eight or ten persons, continuing to call out 'Guarda, guarda!' kept pace with it, walking down the street, stepping out quickly. The meteor passed my window, and I had to turn to the left to see what would be the end of its caprice. After a moment, fearing to lose sight of it behind some houses which jutted out beyond my hotel, I went quickly downstairs and into the street, and was in time to see it again and to join those who were following its course. It was still going slowly, but it was now higher up, and was still ascending—so much so that after a few minutes it hit the cross upon the clock tower of the Chiesa dei Servi and disappeared. Its disappearance was accompanied by a dull report like that of a big cannon twenty miles away when the wind carries the sound.
"To give an idea of the size and colour of this globe of fire, I can only compare it to the appearance of the moon as one may see it sometimes rising above the Alps on a clear night in winter, and as I myself have seen it at Innsbrück—that is to say, of a reddish yellow, with patches on it almost of red. The difference was that you could not see the contours of the meteor distinctly as you could the moon, and that it seemed to be enveloped in a luminous atmosphere of indefinite extent."
This fireball was an innocuous one. We may take next, by way of contrast, the case of one which wreaked terrible damage and loss of life.