But the most striking effect of the earthquake was that a dry fog began in Calabria in February, and overspread until autumn the greater part of Europe, extending even to the Azores. This fog, though not consisting apparently of moisture, was so dense that the sky was quite obscured, appearing a light grey colour instead of blue, while the sun became a blood-red disc. In Calabria the darkness was so great that lights were needed in the houses, and ships came into collision at sea. There was a most disagreeable odour[767]. The fog spreading over all Europe from Calabria was not at all mythical, as we are apt to suppose that similar recorded phenomena of the wonder-loving Middle Ages may have been. The phenomenon was independently reproduced in Iceland the same year, from the 1st to the 11th of June, causing the same darkness at sea, the same atmospheric effects at a distance, but not to so great a distance, and some amount of sickness, but seemingly not aguish or febrile, among the population[768].
Those two great convulsions of the year 1783, each of them the cause of a widely spreading dry fog, may have been conceivably the cause of pestiferous miasmata in the air, such as the corresponding hypothesis of influenza requires; but how little comparable or equivalent were the miasmata—in the one case from the ancient and well-peopled soil of Southern Italy, in the other from the inhospitable Danish colony just without the Arctic Circle! In any case, the earthquakes of 1783 were both too late for the great influenza of the period. The antecedent common alike to the influenza and the earthquakes was the extraordinary droughts, which caused famine and famine-fever in Iceland, and, according to old experience, was probably related to the epidemic prevalence of agues in Britain and on the continent of Europe.
IV.
What kind or kinds of epidemic sickness earthquakes may produce as an effect immediate and at the place, will appear from other instances. One of the most remarkable of earthquakes was that which destroyed Port Royal and nearly all the planters’ houses and sugar-works throughout the island of Jamaica on the 7th of June, 1692. Jamaica had been an English colony for little more than thirty years, during which time it had passed from its state of lethargy under the Spaniards into an emporium of commerce with a rapidly growing population of slaves and whites. The business capital was at Port Royal, wholly built since the British occupation. The site of it was a sandy key or shoal which was said to have risen perceptibly within the memory of original settlers; a writer in September, 1667, said of it: “wherever you dig five or six feet, water will appear which ebbs and flows as the tide. It is not salt, but brackish[769].” A quay had been built along this spit of land, at which vessels of 700 tons could lie afloat. It was here that the havoc of the earthquake was most complete.
Sloane, who had visited Jamaica a few years before, said that the inhabitants expect an earthquake every year, and that some of them were of opinion that they follow their great rains[770]. The year 1692 began in Jamaica with very dry and hot weather which continued until May: then came gales and heavy rains until the end of the month, and from that time until the day of the earthquake, the 7th of June, the weather was excessively hot, calm and dry. The shakes began at 11.40 a.m., and at the third shake, the ground of nearly all Port Royal fell in suddenly, so that in the course of a minute or two most of the houses were under water and the whole wharf was covered by the sea to the depth of several fathoms. The loss of life was, of course, greatest where population was densest; but in the interior of the island the effects on the soil were greater than at the shore: in the north a thousand acres of land sank and thirteen people with it; mountains on either side of a narrow gorge came together and blocked the way; wide chasms appeared in the ground, and on one mountain side there were some dozen openings from which brackish water spouted forth. The first effect in the streets of Port Royal was that men and women seemed all at once to be floundering up to the neck in the wet shifting sand, and were speedily drowned or floated away by the inrushing water. The shakes ceased for days at a time, and then began again, five or six perhaps in twenty-four hours; so that those who had escaped to ships in the bay remained on board for two months, being afraid to come ashore. The weather was hotter after the earthquake than before, and mosquitoes swarmed in unheard of numbers.
During the upheavals or subsidences in Port Royal, and the rushing of water into or from the gapings in the ground, “ill stenches and offensive smells” arose, so that “by means of the openings and the vapours at that time belcht forth from the earth into the air, the sky, which before was clear and blue, was in a minute’s time become dull and reddish looking (as I have heard it compared often) like a red-hot oven.” A very great mortality followed among those who had escaped the earthquake. Some of them settled at Leguanea, others at the place on the bay which became the Kingston of later history, enduring many hardships in their hastily built shelters, from the heavy rains that followed the earthquake, and from want of clothes, food and comforts.
One writes: “Our people settled a town at Leguanea side; and there is about five hundred graves already [20th September, 1692], and people every day is dying still. I went about once to see it, and I had like to have tipt off.” Another says: “Almost half the people that escaped upon Port Royal are since dead of a malignant fever”: and another, referring to the hasty settlement on the bay at Kingston, says “they died miserably in heaps.” But the most interesting information is his next sentence: “Indeed there was a general sickness (supposed to proceed from the hurtful vapours belched from the many openings of the earth) all over the island, so general that few escaped being sick: and ’tis thought it swept away in all parts of the island three thousand souls, the greatest part from Kingstown, only yet an unhealthy place[771].”
That great mortality from a malignant fever after the earthquake of 7th June, 1692, is usually counted an epidemic of the yellow fever which became established at Kingston and Port Royal from that time for at least a century and a half. I have not found any contemporary medical account of it, but all the later writers on yellow fever at Kingston and Port Royal have accepted the tradition that it was yellow fever. But there was one peculiarity, which marks it off from all subsequent epidemics of yellow fever—the sickness was all over the island, so general that few escaped being sick, and was supposed to proceed from the hurtful vapours belched from the many openings of the ground in and near Port Royal. In all subsequent experience yellow fever has been almost confined to the shore or to the ships in the bay[772]. Certainly it has never been all over the island as in 1692, “so general that few escaped being sick”: that is rather in the manner of influenza, although there is nothing to show that the sickness of the interior was so different from that of the shore as to be counted an influenza, or that the mortality of the sick was other than that of a “malignant fever.”
The earthquake at Port Royal in 1692 produced “ill stenches and offensive smells.” The tidal waves, or the subterranean vibrations which caused them, in tearing up the mud at the bottom of the channel at Bridgetown, Barbados, in 1755, had in like manner sent forth a great stench which poisoned the fish. Such offensive vapours were supposed in former times to come, as in a figure, from “the bowels of the earth”; and undoubtedly the sulphurous fumes which have overhung the region of Sicilian earthquakes must have had a source as deep as the strange minerals or “fossils” of Boyle’s hypothesis. But, while the commotion of an earthquake is deep, it is also superficial; whatever miasmata issue from the ground in the ordinary alternations of wet and drought, would be discharged into the atmosphere in unusual quantity and with unusual force in such disturbances of soil as sunk Port Royal in 1692 or were felt at Barbados across the whole width of the Atlantic in 1755. Nor is that effect upon miasmata instantaneous or quickly past; in Jamaica the rumblings and shakes lasted for nearly two months, during which time the pressure upon the gases in the subsoil must have been such as to make them pass into the atmosphere in stronger ascending currents than the mere alternations of moisture and drought would have done. And just as the ordinary seasonal changes in the level of the ground-water are of little or no account for miasmatic-infective disease unless the soil in which they occur be full of organic impurities from human occupancy, so one may reason that the great cataclysmic changes of the earth’s crust are, in this hypothesis of influenza, of most account as touching the stratum of soil wherein lie organic impurities, and as touching those areas of the surface,—the sites of cities, the populous plains, the shores of bays, the bottoms of harbours or any other definite spots—in which the products of organic decomposition are present in largest amount and, perhaps, of somewhat special kind. Such impurities of the soil are indeed a vera causa of infective disease, known to be capable of the effect which has to be accounted for; and, as discharged into the air in great volume and with great force by some upheaval, they would make a local beginning of that “aer inimicus” which the Roman poet figures as creeping like a mist from one region of the heavens to another so that it corrupts each successive tract of air with its own baleful qualities, “reddatque sui simile atque alienum.”