In his Kosmos lectures Alexander von Humboldt mentioned the sudden appearance of the island Sabrina in the context of volcanism. A possible source of his knowledge can be found in the Transactions of the Royal Society London in 1812. There Captain S. Tillard described his adventures of witnessing the eruption of an underwater volcano in the Azores in 1811 that resulted in the appearance of an island. Tillard explored the island that he named Sabrina and published the description of his adventures in 1812. Here we present an excerpt of his account focussing on detail of the eruption and the island's evolution. For our digital update of the Kosmos lectures we support his account with modern photographs that provide an excellent visualisation of his description:

Captain Tillard's Eye Witness Account

APPROACHING the island of St. Michael's, on Sunday the l2th of June, 1811 , in His Majesty's Sloop Sabrina, [..] we occasionally observed, rising in the horizon, two or three columns of smoke,[..]. [..] from the smoke increasing and ascending [..] and having heard [..], that in the preceding January or February a volcano had burst out within in the sea near St. Michael’s, we immediately concluded that the smoke we saw proceeded from that cause [..] On our anchoring in the road of Ponta del Gada, we found this conjecture correct [..]; the eruption of January having totally subsided, and the present one having only burst forth two days prior to our approach, and about three miles distant from the one before [..].

I set off from the city of Porta del Gada on the morning of the 14th, in company with Mr. Read, the Consul General of the Azores and two other gentlemen. After riding about twenty miles across the NW end of the island of St Michael’s, we came to the edge of a cliff from whence the volcano burst suddenly upon our view in the most terrific and awful grandeur. [..]

Imagine an immense body of smoke rising from the sea, the surface of which was marked by the silvery ripling of the waves, occasioned by the light and steady breezes incidental to those climates in summer. In a quiescent state, it had the appearance of a circular cloud revolving on the water like an horizontal wheel, in various and irregular involutions, expanding itself gradually on the lee side [..]

Suddenly a column of the blackest cinders, ashes, and stones would shoot up in form of a spire at an angle of from ten to twenty degrees from a perpendicular line, the angle of inclination being universally to windward: this was rapidly succeeded by a second, third, and fourth, each acquiring greater velocity, and overtopping the other till they had attained an altitude as much above the level of our eye, as the sea was below it.

As the impetus [..] diminished, and their ascending motion had nearly ceased, they broke into various branches resembling a groupe of pines [..] These again forming themselves into festoons of white feathery smoke in the most fanciful manner imaginable, intermixed with the finest particles of falling ashes, which at one time assumed the appearance of innumerable plumes of black and white ostrich feathers surmounting each other; at another, that of the light wavy branches of a weeping willow.

During these bursts, the most vivid flashes of lightning, continually issued from the densest part of the volcano; and the cloud of smoke now ascending to an altitude much above the highest point to which the ashes were projected, rolled off in large masses of fleecy clouds, gradually expanding themselves before the wind in a direction nearly horizontal, and drawing up to them a quantity of water spouts, which formed a most beautiful and striking addition to the general appearance of the scene.

That part of the sea, where the volcano was situated, was upwards of thirty fathoms deep, and at the time of our viewing it the volcano was only four days old. Soon after our arrival on the cliff; a peasant observed he could discern a peak above the water: we looked, but could not see it [..] However, in less than half an hour it was plainly visible, and before we quitted the place, [..] about three hours from the time of our arrival, a complete crater was formed above the water, not less than twenty feet high on the side where the greatest quantity of ashes fell; the diameter of the crater being apparently about four or five hundred feet.

The great eruptions were generally attended with a noise like the continued firing of cannon and musquetry intermixed, as also with slight shocks of earthquakes [..] one of the most magnificent bursts took place which we had yet witnessed, accompanied by a very severe shock of an earthquake. The instantaneous and involuntary movement of each was to spring, upon his feet [..] we observed a large portion of the face of the cliff, about fifty yards on our left, falling, which it did with a violent crash. So soon as our first consternation had a little subsided, we removed about ten or a dozen yards further from the edge of the cliff, and finished our dinner.

On the succeeding day, June 15th, having the Consul and some other friends on board, I [..] proceeded with the ship towards the volcano, with the intention of witnessing a night view; [..] we were greatly disappointed, from the wind freshening and the weather becoming thick and hazy, and also from the volcano itself being clearly more quiescent than it was the preceding day. It seldom emitted any lightning, [..]. On passing directly under the great cloud of smoke, about three or four miles distant from the volcano, the decks of the ship were covered with fine black ashes, which fell intermixt with small rain. [..]

On opening the volcano clear of the NW part of the island, after dark on the 16th, we witnessed one or two eruptions that, had the ship been near enough, would have been awfully grand. It appeared one continued blaze of lightning; [..].

Returning again towards St. Michael's on the 4th of July, I [..] pass with the ship very close to the island, which was now completely formed by the volcano, being nearly the height of Matlock High Tor, about eighty yards above the sea. At this time it was perfectly tranquil, which [..] determined me to land, and explore it more narrowly.

I left the ship in one of the boats, accompanied by some of the officers. [..] we perceived that it was still smoking in many parts, and upon our reaching the island found the surf on the beach very high. Rowing round to the lee side, with some little difficulty, by the aid of an oar, as a pole, I jumped on shore, and was followed by the other officers. We found a narrow beach of black ashes, from which the side of the island rose [..] too steep to admit of our ascending; and where we could have clambered up, the mass of matter was much too hot to allow our proceeding more than a few yards in the ascent.

The declivity below the surface of the sea was equally steep, having seven fathoms water, scarce the boat's length from the shore, and at the distance of twenty or thirty yards, we sounded twenty-five fathoms.

From walking round it, in about twelve minutes, I should judge that it was something less than a mile in circumference; but the most extraordinary part was the crater, the mouth of which, on the side facing St. Michael's, was nearly level with the sea. It was filled with water, at that time boiling, and was emptying itself into the sea, by a small stream about six yards over, and by which I should suppose it was continually filled again at high water. This stream, close to the edge of the sea, was so hot, as only to admit the finger to be dipped suddenly in, and taken out again immediately. It appeared evident, by the formation of this part of the island, that the sea had, during the eruptions, broke into the crater in two places, as the east side of the small stream was bounded by a precipice, a cliff between twenty and thirty feet high forming a peninsula of about the same dimensions in width, and from fifty to sixty feet long, connected with the other part of the island by a narrow ridge of cinders and lava, as an isthmus of from forty to fifty feet in length, from which the crater rose in the form of an amphitheatre.

This cliff, at two or three miles distance from the island, had the appearance of a work of art resembling a small fort or block house. The top of this we were determined, if possible, to attain; but the difficulty [..] was considerable; the only way [..] was up the side of the isthmus, which was so steep, that the only mode by which we could effect it, was by fixing the end of an oar at the base, with the assistance of which we forced ourselves up in nearly a backward direction.

Having reached the summit of the isthmus, we found another difficulty, for it was impossible to walk upon it, as the descent on the other side was immediate, and as steep as the one we had ascended; but by throwing our legs across it, as would be done on the ridge of a house, and moving ourselves forward by our hands, we at length reached that part of it where it gradually widened itself and formed the summit of the cliff, which we found to have a perfectly flat surface [..].

Judging this to be the most conspicuous situation, we here planted the Union, and left a bottle sealed up containing a small account of the origin of the island, and of our having landed upon it, and naming it Sabrina Island.

Within the crater I found the complete skeleton of a guardfish, the bones of, which being perfectly burnt, fell to pieces upon attempting to take them up [..] By the account of the inhabitants on the coast of St. Michael's, great numbers of fish had been destroyed during the early part of the eruption, as large quantities, probably suffocated or poisoned, were occasionally found drifted into the small inlets or bays.

The island, like other volcanic productions, is composed principally of porous substances, and generally burnt to complete cinders, with occasional masses of a stone, which I should suppose to be a mixture of iron and lime-stone; but have sent you specimens to enable you to form a better judgment than you possibly can by any description of mine.

Text Source:
Tillard, S. (1812) “A Narrative of the Eruption of a Volcano in the Sea off the Island of St. Michael” Philosophical Transactions of the Royal Society of London 102: pp. 152-158.