The following is my translation of an article called: 'Merkwürdige Regenfälle' von Dr Georg Stehli. It appeared in a German popular science magazine, Kosmos Handweiser für Naturfreunde 1923, Heft 7, Seiten 171-174. I'm not aware of any previous translation.
Trevor Dykes.

Remarkable rainfalls
Among the natural phenomena which have long been viewed with astonishment as miraculous, until the true nature was revealed by careful scientific study, belong a number of remarkable 'rain' showers of things falling down which do not usually occur in the sky, such as living animals, plants, blood, sulphur and other such items. Suddenly material turned up on the ground, and no person could explain from whence it had come. One did not know the causes; this sudden presence could not possibly have anything to do with natural events; therefore, said popular belief; it has fallen from the heavens. The actual explanations are both simple and instructive.

Reports from earlier times about 'blood rain' are truly countless. The phrase does not have an exactly pleasant ring to it, and it may prove unusually worrying should one suddenly see streams of red liquid falling down from the heights of the sky, reminiscent of a particularly valuable juice, the carrier of our life, or if puddles with small fish suddenly appear -this generally happens within a single night- lively coloured as blood. It is no wonder that such appearances were held, in medieval times, to be omens of danger from wars or plagues. Today it is widely enough known that this 'blood rain', which occurs repeatedly in volcanic tropical lands such as, for example, the island of Java but is rare for us, happens due to millions of microscopically small single-celled algae of the genus Sphaerella, as they give the rain water the strange red colour. These 'blood' algae (Sphaerella nivalis to be precise) are also what cause the snows of the Alps and almost all other high mountains in Europe, and also in polar areas, to often be tinted with rose or dark red. However, this is not the complete explanation; then chemical analysis of such 'blood rain' in Java also revealed relatively large quantities of very fine, yellow-brown mineral dust of undoubtedly volcanic origins alongside of the 'blood' algae. And that brings us, especially in the tropics, to the frequent dust rains which, almost without exception, result from clouds of dust thrown up into the air, particularly ash from volcanic eruptions. Precisely such forms of volcanic ash can hang in the air for long stretches of time and, in the right conditions, can be carried for incredible distances by currents, only then to be released again as a rain of dust.

I will never forget the occasion when, as I was in a high lying field in the Black Forest one day in May, a grey-yellow smoke suddenly began to ascend from a distant forest, which was over an hour's walk away from me. Was there a fire? The smoke whirled and waved chaotically in the air and moved forwards ever more quickly. No, that was not a fire. Ever nearer came that misty cloud and it fastened its yellow arms round me.

I was standing in the middle of a rain of pollen. Yes, pollen it was, from the countless fir trees of our forests. That was the solution to the riddle. Pollen was stuck to my clothes, it lay between the grass and plants, and swept in a whirling storm into a racing dance and a damp grave. On the surface of the water of a nearby pond were floating millions and millions of bits of yellow pollen. It really had rained 'sulphur'.

And just imagine the terrifying effect that such 'sulphur rain' could have had, especially in combination with a strong storm, in earlier times! When, at the same time, both sulphur and fire rained down! War or plague were underway, or the end of the world, as one had so feared, was staring one in the face.

What does not fall from the sky! On a stroll after a heavy, storming rain we may find the path covered with masses of silk thin worms. The fact that these animals are suddenly there, where they surely had not been but a short while before, is enough for people to believe in worm rains. However, this appearance is easily accounted for. These small nematode worms (Mermis nigrescens) lie quietly rolled up in the damp ground in order to slowly mature, and into which they arrived after leaving the bodies of certain insects (one-day flies, beetles), and that is where they spent their larval stage. After the warm rain they are set slowly into motion and appear, for a short while, on the ground or in the leaves of low-growing shrubs.

Or the 'frog rain', which is connected with the social migrations of juvenile Grass frogs, who first obtain their frog form and then move to the land from water in such hordes, and often following a fall of rain, that the old legend finds a thoroughly natural explanation. The old zoologist Rösel von Rosenhof, a very intelligent observer of our animal world from the eighteenth century, had already recognised the true cause of 'frog rain'. "When, however, others discovered my opinion", he wrote in his well worth reading 'Natural history of the frogs of this land' (Nuremberg, 1758), "so they laughed at me and maintained, in all seriousness, that they had seen 'frog rain' for themselves on more than one occasion. When I asked the same whether, during such a rain, the frogs all landed on their bellies, so they either said they could not remember or had to admit that such had not happened. Those, however, who maintained that they had recently seen it raining frogs before the gates at the same time as it had rained in the city, knew of no answer to my question, why then were there no frogs in the city. As far as my opinion is desired by those who believe that small rain frogs emerge from the larger rain drops or out of the earth, in that it can clearly be seen that there is instantaneously a hopping frog, then this is contradicted by the completeness of these small frogs and their slow growth. If somebody were to tell me that it is impossible for so many frogs to move simultaneously from the water to the land, and the quantities after a shower can indeed be prodigious, then whoever made such an accusation must be unaware that a single female frog produces 600 eggs, yes, 600. As that is the nature of the thing, and at least 600 eggs from a single female had been laid in the water, and in some places, however, there are many more frogs than that and also more than a single female, so it is entirely possible that countless quantities of young frogs can emerge from a single pond."

But it is not only frogs but also toads which 'rain' down on occasions from the sky. According to Stiller in August 1804 (!), a deep and dark bank of cloud arose in southern France, thunder cracked, a hurricane blew and, at the same instant, toads began to rain down. The streets and fields were suddenly literally overfilled with toads, even five deep on top of one another.

And also today fish sometimes fall from the skies, and for this I have only but recently received an account from a German engineer in Argentina, an also keen, careful and experienced observer of nature. "It was a day in the year of 1915" it states in the letter, "and their fell in the province of Santa Fé a very strong rain of 100mm in only a few hours, which is not unusual here; and in the open area in front of my factory, which is filled with sawn planks and thus always kept dry, large puddles had built up and there were a lot of fish of up to 20cm in length swimming around in them. As I was going home at midday I myself fetched some of them out, and put them in a basin of water for my domestic ducks. -These puddles of water in front of the factory quickly dried out, and no mud had developed for the fish to bury themselves into, so they undoubtedly arrived with the rain, and I have a number of German gentlemen as eye witnesses of that." The position of the factory and a closer description of the area rules out that fish eggs could have been transported in by water birds and, as it is also not possible that a high tide could have had anything to do with this, the only remaining cause for this magnificent 'fish rain' is the wind, and that is always strong in association with this kind of rain. This storm must naturally have been abnormally strong in order to have taken hold of such quantities of relatively heavy animals from the distant lakes and ponds, and then to have more or less supported their weight.

Only the meteor jelly or frog spawn 'rain' remains for mention because, even into recent times, this superstition has also been shared by learned persons and, due to an unusual chain of circumstances, it has received further nourishment as shown by a report before me now (Dr Otto Hahn, Bericht über zwei Gallertmeteorittenfälle, Jahresheften des Vereins für vaterl. Naturkunde in Württemberg, 1882) and about this, unfortunately, I can only give but a brief sketch rather than going into detail. It was early in the year of 1911 that I was first able to closely investigate 'meteor jelly' that had apparently fallen from the sky in Schwabia. I received a further specimen in that same year from Emden in East Freesia (which occurred in March) and another from Essen (fallen in July) and, in the year 1913, came two lumps discovered in summer on a lane in Upper Schwabia. In all cases these lumps resembled a beefsteak in terms of shape, size and thickness, although they were rather unappetising masses of slime with blue-white-green colours and their brain-like folds. At the lightest of a touch the clumps would begin to shiver. Under the microscope I saw that the jelly was perforated by lots of pearl necklace-like, unbranching chains, and these were built by a single-celled alga of the many specied genus of Nostoc. Some kind of evidence for animal material, such as egg stocks of frogs or frog spawn, which could have suggested the involvement of aquatic birds, could not be found despite repeated examinations. These algae, which, with their peculiar construction and appearance, received the name of Jelly- or Shivering algae (Nostoc commune), are fairly common on damp soil, meadows and the like, where they quickly develop into large slimy masses after rain following prolonged drought, and they can be found in profusion.

The country people were unable to account for the sudden appearance of these slimy things, and so they assumed they had to have fallen from the sky and called them shooting stars, jelly rain or frog spawn rain. The term shooting star even found its way into science with the Latinised name of Tremella meteorica. A precise examination, however, soon showed that the belief in an extra-terrestrial origin for meteor jelly was wrong. Instead, for a fairly long time, it was thought that these things might build up in the stomachs of certain birds (particularly cranes, wild ducks and a few other aquatic birds) as uncommonly swollen egg stocks from frogs, which were then ejected again; but this explanation could also not be maintained.

It should go remarked that these odd phenomena also offer interest to cultural historians as well as to scientists of natural history. During the time of the medieval witch hunts, the discovery of such jellied masses was taken as an especially bad sign that the owner, male or female, of the relevant property stood in league with the devil and his demons; the jelly was seen as the vomited meal of witches or the remnants of devilish feasts left at their dancing places. Today, on the other hand, jelly algae are consumed as delicacies in China, Bolivia and Ecuador. How times change!

An index of more of my translations of old Kosmos articles can be found at:

Kosmos Translations Archive

A number of Mesozoic (and post-Mesozoic) location summaries can be found at Localities.