AND OF THE PHYSICAL SCIENCES. 



15 



GEOLOGY AND PHYSICAL GEOGRAPHY. 



GREAT ERUPTION OF THE VOLCANO OF COSIGUEINA. 

 Iif America, I'etween the 10th and 15th degrees of north latitude, there are at least 

 twenty-one active volcanoes. All these are situate in the provinces of Guatiraala and 

 Nicaragua, which lie between Mexico and the Isthmus of Panama. The following 

 account of the last great eruption of the volcano of Cosigiieina is translated from the 

 official reports published by the government of Guatiranla. 



On the 20th of Januai-y 1835, at half-past 6 o'clock in the morning, the volcano 

 of Cosigiieina broke out, and the vapour which arose was beautiful. At 11 o'clock 

 it covered the whole of the territory around Nacaome, and at noon the obscurity was 

 so intense as to exceed all description. 'We had then a night of 18 hours' duration, 

 while tremulous movements of the earth, noises, tempests of thimder and lightning, 

 caused by the combustible matter which filled the atmosphere, and an impetuous wind 

 impellinn- a heavy shower of ashes, rendered that night a period of distress and horror. 

 The morning of the 21st was melancholy, though tlie light penetrated through the 

 dense vapours, and the sun sometimes showed a pale and saifi"on- coloured countenance. 

 The 22d resembled the preceding day, and the night was passed rather quietly until 

 12 o'clock. There then commenced a hollow growling sound, vehement and alarm- 

 ing, which continued without interruption or diminution for at least 13 minutes. This 

 noise was instantaneously followed by some terrific detonations, as loud as reports from 

 artillery of the largest calibre. At a quarter past 12, a violent tremulous movement 

 indicated a fresh eruption, which was soon confirmed by the ascent of a volume of 

 smoke. At half-past 2 there was a sort of twilight, which served to interrupt a night 

 of 36 hours, and the noises continued, being louder than on the 20th. A reflection 

 of red light occasionally broke through the obscurity of the atmosphere; but so con- 

 stant and terrible were the explosions, and the thunder and lightnmg, that it appeared 

 to threaten the annihilation of the world itself. The 24th commenced much in the 

 same manner as the 21st. 



That a volcano should renew its eruptions, vomit forth lava and ashes, and occasion 

 damage, might be expected to occur. But that the eruption of a hill, not one-eighth 

 so hio-h as Pacaya, should have darkened for several days the half of central America, 

 and covered a space exceeding perhaps 15,000 square leagues with lava and ashes, to 

 tlic height or thickness, in some places, of half a yard, in others a quarter, and no 

 where less than two inches ; that men should fly to the mountains, and wild beasts 

 to the toivns, as has happened at Nacaome, in Pcsperi, Corpus, Ila del Tigre, Con- 

 chagua, el Puerto, &c. ; that the fishes should have perished in the rivers, the birds 

 be suffocated by dust, the reptiles and quadrupeds by slime ; and that Man should re- 

 main unhurt amidst this convulsion of the elements — is a thing truly astonishing, and 

 scarcely to be credited. Cosigiieina continued, like Isalco, to vomit exhalations until 

 the 5th of February. The atmosphere cleared up slightly about 6 o'clock in the 

 evenin" and 8 in the morning; but when the wind began to blow, clouds of dust en- 

 veloped Nacaome on all sides. Hitherto no bad effects had resulted except inflamma- 

 tion about the head, eyes, mouth and throat, which caused very severe coughing. It 

 is extraordinary that the inhabitants of Nacaome were able to endure the showers of 

 dust without being suffocated, especially as it has been found to be loaded with sul- 

 phur, iron, and antimony, and to be very inflammable. Cattle and flocks perished, 

 and an unusual mortality was expected from the deficiency of pastm'c and from the 

 deterioration of the water. 



At San IMarcos, from the 23d to the 29th of January, the atmosphere of the city 

 was observed to be impregnated with smoke and ashes; and on the 24th particularly, 

 so great a shower of ashes fell, tJiat the roofs of all tlie houses were whitened with it. 

 Until 9 o'clock in the morning, repeated explosions were heard, by which great 

 alarm was created through the various towns, under the impression that they proceeded 

 from the volcano of Quezaltenango ; and the city was presently deserted by many of the 

 merchants, who removed themselves to a distance, for the better security of their fa- 

 milies. 



On the 20th of January in the morning, the inhabitants of the town of Masaya 

 heard towards the north-east some faint volcanic sounds, whilst those of the to\\'n of 

 Viejo observed a sheet of fire rising perpendicularly to a considerable elevation, and 

 afterwards dechning towards the north. This was the same appearance which was ob- 

 served in the department of Segovia, where at the same time some reports were heard, 

 and some shght shocks were experienced. 



In Leon, the capital, and in the department of Granada, the catastrophe had not been 

 perceptibly felt \mtil the dawn of the 25th, when the explosion developed itself to such 

 a degree, that from 1 o'clock the sky was darkened with an opacity which continued to 

 deepen till 11 in the morning, when the inhabitants of the capital were enveloped in a 

 most frightful darkness, whilst terrific reports were heard, and showers of ashes were 

 precipitated over all the face of the country. 



I'his natui-al event produced an impression in the minds of the superstitious inhabi- 

 tants that it proceeded fi-om the Divine anger ; and whilst the people ran in crowds to 

 the temples to implore the mercy of Heaven, the garrison of the town diverted their 

 consternation by discharges of cannon and musketry. This was done by order of the 

 government, who, by the advice of some intelligent chemists, directed discharges of 

 artillery to be fii*ed, rockets to be let off, fires to be lighted, and the bells of all the 

 churches to be rung, in order to dissipate the dense vapours with which the atmo- 

 sphci'c was impregnated. 



The qmckness was astonishing with which, on the 23d, all the atmosphere was filled 

 with volcanic matter, from Nicaragua, as far as the department of that name, towards 

 the south-east. The murky clouds then gi*adually moved towards Nandayme, where, 

 about 3 o'clock in the afternoon, the darkness reigned over the city, and extended 

 to the town of Rivas. The same thing occurred in the department of Granada, the 

 towns in which suffered nearly to the tame extent as in Leon, whilst those of JMatagal- 

 pa in Segovia experienced a night of 3G hom-s' duration. 



Fortunately not a single life was lost, though in the immediate neighbourhood of 

 the mountain where the eruption occiurcd some cattle were destroyed. It does not 

 appear that the damage will be so great as was conceived at the time of the catastro- 

 phe, because the sand or ashes that have been scattered over the plains wiU wonder- 



fully fertilize them — a fact which has been ascertained in some places watered a 

 few days afterwards by the rain, where the plants showed a most luxuriant appear- 

 ance, the pasture was rapidly rising, and every thing seemed to promise a forward 

 spring. 



The agitation of the air, when winds prevail, usually affects people with disagree- 

 able sensations, and does gi-eat injury to cattle, on account of the dust which fills the 

 atmosphere, to such a degree that it is impossible to see even for the distance of a 

 league. 



On the 9th of I^Iarch, a commission went to observe the volcano, and they could 

 not recognise the coast with perfect distinctness, or throughout its entire extent, in 

 consequence of the cloud of smoke which covered the plains. A forest, which appeared 

 to have survived many changes of the earth's surface, had disappeared. Two islands 

 have been formed in the sea — one being 800 yai-ds, and the other 200, in its greatest 

 extent. Their composition consists of pumice-stone and scorite, with a number of 

 pyrites of a golden colour, and having a strong metallic odour. Some shoals in the 

 sea, from 500 to 600 yai'ds long, were formed. In one of them a large tree was fixed 

 with its branches downwards, and its roots raised up. The river Chiqdto, which ran 

 towai-ds the north-west, was completely choked up, and another river, six yards broad, 

 had sprung up in the opposite direction. 



A party proceeded from the town of El Viejo to make another observation, by 

 which it was ascertained that the farms of Sapasmapa and Cosigiieina, situate in 

 the immediate neighbourhood of the volcano, had disappeared. From the first not 

 a single head of cattle had escaped. In the latter 300 quadrupeds were found remain- 

 ing, but in a weak and wretched condition, and they were not expected to survive. 

 The remains of immense numbers of quadrupeds and birds were found lying in the im- 

 mediate neighbourhood of the volcano. A vessel, which on the 20th of last month 

 was near the coast, having a crew of seven men, was supposed to have been destroyed, 

 £ince no information respecting it was received. 



In the city of Leon the ravages done have been less, for the darkness there was 

 not very great, and the same may be said of the showers of dust. The noise travelled 

 to Costa Rica, where the cause was considered to be very near. The Colombian gal- 

 ley Boladora, which left Acapulco on the 20th ult. for the Rcalcjo, experienced the 

 darkness at 20 leagues from the shore, as well as such a copious shower of dust that 

 the crew were apprehensive of being suffocated; and they were occupied for 48 hours 

 in cleai'ing the vessel with spades. Not being able to make for the Realejo on account 

 of the darkness, they directed their course to Puuta Arenas, with the full conviction 

 that the whole state of Nicaragua had disappeared. The volcano continued vomitin-T 

 fn-e and smoke, and causing at intervals a trembling of the earth. 



Until further information arrives, it is impossible to calculate precisely the distance 

 to which the showers of cinders extended and the noises were heard. The de- 

 tonations wore so loud as to be heard at Ciudad Real de Chiapas, which is 325 leao-ues 

 from the mountain in one directiun, and at El Pcten, which is 322 leagues in another • 

 and, as it is probable they could have been heard fai'ther, we may estimate that the 

 eruption affected the district, extending around the mountain 350 leagues in every di- 

 rection. Even at Dolores, in the district of Peten, showers of ashes, volcanic reports, 

 and earthquake shocks, were experienced. 



In the time of the Roman Emperor Titus, in consequence of an eruption of Vesu- 

 vius, the ashes are stated to have been thrown into Africa, a story which has been 

 considered incredible by some modern writers. This ei-uption of Cosigiieina shows the 

 statement of the ancients to be by no means improbable. 



Footmarks of an Extikct Anjmai. in the Solid Rock. — Baron Alex. Von 

 Humboldt has again arrived in Paris. At a meeting of the Academy of Sciences on 

 the 17th August 1835, he du-ccted the attention of the members to the prints of the 

 footsteps of a quadruped in the variegated sandstone, or Ounte sandatein, of Hildburg- 

 hauscn. It is an animal of the Plantigrada division, which had traversed the rock in 

 various directions while soft. A stone, from ten to twelve feet long, and three to four 

 wide, containing these impressions, has been sent to the Collection of Geology at Ber- 

 hn, of which the Baron submitted to the Academy a beautiful drawing. There are 

 four 01' five impressions of a smaller "species, which cross those of the larger quadruped 

 at right angles, and are remarkable for the unequal dimensions of the fore and hind 

 feet ; all of them have the impressions of five toes. The rock is covered with them 

 as with a net-work, and here and there sinuous serpular concretions are visible per- 

 haps the plants on which the animals walked, or probably some accidental defect in 

 the process of drying. The great importance of this discovery consists in the posi- 

 tion occupied by this sandstone in the chronological series of rocks. 



Shock of an Earthquake at Chichester. — On Monday the 10th Aagust 

 1835, between eleven and twelve o'clock, many of the inhabitants of Chichester were 

 awakened from their sleep, and much alarmed by two shocks of earthquakes. It is 

 nearly twelve months since the last of these awful phenomena, and people began to 

 hope that they would have entirely ceased. These shocks, however, were considered 

 generally to have been less violent than most of those which had occurred last year. 



Floating Islands From the earliest times, authors have described those sin- 

 gular geological phenomena called floating islands. Pliny tells us of the floating 

 islands of the Lago dc Bassanello, near Rome. Neai' St Omer's, in the province of 

 Artois in France, there is a large lake, in which there ai'e several floating islands, 

 some of which are inhabited; on one of them there was a church, and a religious 

 convent of Bcmardines. These islands are moved in difii"erent directions by the wind ; 

 and sometimes they are moored to the side with ropes. There are floating islands in 

 Lochlomond, Scotland, and in the lake of Derwent-vvater, Cumberland: such islands 

 appear and disappear. The latter, which had been under water for some time past, 

 reappeared about the 7th September 1835, and attracted the attention of nume- 

 ro'js visitors. Mr A. Pittingal, junior, in 1829, described a floating island about a 

 mile southward of Newbury Port, in Massachusetts, Essex county. North America, 

 140 poles in length, and 120 in breadth. It is covered with trees; and in summer, 

 when dry weather has long continued, it descends to the bottom of the lake. 



