414 Royal Society. 
The observations recorded in this Journal are those of the baro. 
meter, and of two thermometers, one in, and the other out of doors; 
taken at sunrise, noon, sunset, and midnight, in each successive day 
from the Ist of June, 1834, to the end of the year. 
«« Some Account of the Volcanic Eruption of Coseguina in the 
Bay of Fonseca, commonly called the Coast of Conchagua, on the 
Western Coast of Central America.” By Alexander Caldcleugh, 
Esq., F.R.S. 
The particulars recorded in this narrative are derived partly from 
a voluminous collection of official reports transmitted from the au- 
thorities in various towns to the government of Central America, 
_ and partly from the information of intelligent eye-witnesses of the 
phenomena. The eruption occurred on the 19th of January, 1835, 
and was preceded by a slight noise, accompanied with a column of 
smoke issuing from the mountain, and increasing till it took the form 
of alarge and dense cloud, which, when viewed from a distance of ten 
leagues to the southward, appeared like an immense plume of white 
feathers, rising with considerable velocity and expanding in every 
direction. Its colour was, at first, of the most brilliant white; but 
it gradually became tinged with grey; then passed into yellow; and 
finally assumed a beautiful crimson hue. In the course of the fol- 
lowing days several shocks of an earthquake were felt, the last of 
which were most terrific. On the morning of the 22nd, the sun had 
risen in brightness; but a line of intense darkness denoted the pre- 
sence of the same cloud which had before presented such remarkable 
appearances, and which, extending with great rapidity, soon ob- 
scured the light of day ; so that in the course of half an hour the 
darkness equalled in intensity that of the most clouded night: per- 
sons touched without seeing one another ; ‘the cattle hurried back 
to their folds ; and the fowls went to roost, as on the approach of 
night. This atmospheric darkness continued with scarcely any di- 
minution for three days; during the whole of which time there fell 
a fine impalpable dust, covering the ground at St. Antonio to the 
depth of two inches and a half, and consisting of three layers of 
different shades of grey colour: and for ten or twelve succeeding 
days the sky exhibited a dim and murky light. At Nacaome, to 
the northward of the volcano, the same degree of darkness was ex- 
perienced, and the deposit of ashes was from four 'to five inches in 
depth, and exhaled a fetid sulphureous odour, which penetrated 
through every interstice in the buildings. The complete obscurity 
was only occasionally broken by the lightning, which-flashed in every 
direction, while the air was rent with loud and reiterated explosions 
like the discharges of artillery, which accompanied each eruption of 
volcanic matter, and conspired to strike the deepest terror, and to 
spread among the inhabitants a universal panic that the day of judge- 
ment was arrived. On the 24th the atmosphere became clearer, and 
the houses were found covered to the depth of eight inches with ashes, 
in which many small birds were found suffocated. Deer and other 
wild animals flew to the town for refuge, and the banks of the neigh- 
bouring streams were strewed with dead fish. In Segovia, and as 
far as eight leagues from the volcano, the showers of black sand were 
