weighed upwards of 60 pounds. When these large vitrified masses either struck against each other in the air, or fell on the ground, they broke in many pieces, and covered a large space around them with vivid sparks of fire, which communicated their heat to every thing that was combustible. In an instant the town and country about it were on fire in many parts; for in the vineyards there were several straw huts, all of which were burnt. A great magazine of wood in the heart of the town was all in a blaze; and had there been much wind the flames must have spread universally, and all the inhabitants would have infallibly been burnt in their houses; for it was impossible for them to stir out. Some who attempted it with pillows, tables, chairs, the tops of wine casks, &c. on their heads, were either knocked down, or soon driven back to their close quarters under arches, and in the cellars of their houses. Had the eruption lasted an hour longer, Ottaiano must have remained exactly in the state of Pompeia, which was buried under the ashes of Vesuvius just 1700 years before, with most of its inhabitants, whose bones are to this day frequently found under arches and in the cellars of the houses of that ancient city.

The number and size of the stones, or, more properly speaking of the fragments of lava, which were thrown out of the volcano in the course of this eruption, and which lay scattered thick on the cone of Vesuvius, and at the foot of it, were incredible. The largest they measured was in circumference no less than 108 English feet, and 17 feet high. It was a solid block, and much vitrified: in some parts of it there were large pieces of pure glass, of a brown yellow colour, like that of which common bottles are made, and, throughout, its pores seemed to be filled with perfect vitrifications of the same sort. The spot where it fell was plainly marked by a deep impression, almost at the foot of the cone of the volcano; and it took three bounds before it settled, as was plainly perceived by the marks it has left on the ground, and by the stones which it pounded to atoms under a prodigious weight. Another solid block of ancient lava, 66 feet in circumference, and 19 feet high, being nearly of a spherical shape, was thrown out at the same time, and lay near the former. This stone had the marks of having been rounded, nay almost polished, by continual rolling in torrents, or on the sea-shore; but it had undoubtedly been, in that state, thrown out of the volcano, and may therefore be the subject of curious speculations. Another block of solid lava that was thrown much farther, and which lay in the valley between the cone of

Vesuvius and the Hermitage, was 16 feet high, and 92 in circumference, though it appeared, by the large fragments that lay round, and were detached from it by the shock of its fall, that it must have been twice as considerable when in the air. There were thousands of very large fragments of different species of ancient and modern lavas, that lay scattered on the cone of Vesuvius, and in the vallies at its foot; but these three were the largest of those they measured. They measured two other stones in the valley between Somma and Vesuvius; the one was 22 feet long, 13 feet broad, and 10 feet high; the other, 11 feet high, and 72 feet in circumference.

Astronomical Observations relating to the Mountains of the Moon. By Mr. HERSCHEL.

[1780.]

Nov. 30. 1776, six o'clock in the morning, a rock, situated near what Hevelius calls Lacus niger major, was measured to project 41.56. Then, by Hevelius's method the perpendicular height of the rock is found to be about one mile. The same morning, a great many rocks, situated about the middle of the disk, projected from 25".93 to 26′′.56. These rocks are all less than half a mile high.

Jan. 13. 1780, seven o'clock, Mr. H. examined the mountains in the moon; but there was not one of them that was fairly placed on level ground, which is a condition very necessary for an exact measurement of the projection. If there should be a declivity on the moon before the mountains, or a tract of hills placed so as to cast a shadow on that part before them which would otherwise be illuminated, it is plain that the projection would appear too large; and, on the contrary, should there be a rising ground before them, it would appear too little. As far as he was able to judge of the direction of the line of illumination, the highest hill projected 26".31: thence we find, as before, that the perpendicular height is less than half a mile.

Jan. 14. 11 o'clock, he took the projection of the highest mountain, which was situated at the western edge. It measured 24".68, or about 27 miles; and the perpendicular height comes out less than half a mile. There was not another mountain in the edge of the disk so high as this. Jan. 17. seven o'clock, a very high mountain projected no less than 40′′.625. Its situation is in the south-east quadrant; and the perpendicular height of the mountain is 1m.47, or less than a mile and a half.

From these observations, Mr. H. believes it is evident, that

the height of the lunar mountains in general has been greatly over-rated; and that, when we have excepted a few, the generality do not exceed half a mile in their perpendicular elevation.

A Storm of Lightning at East Bourn, Sept. 17. 1780.-[1781.]

ABOUT nine in the morning, a black cloud passed over the house of James Adair, Esq., Recorder of London. He saw some shafts of lightning pass from it to the sea, and while standing in the window viewing them, a flash threw him several yards backward on the floor, where he remained some time, sensible, but unable to move, see, or speak. His coat and breeches were torn, and part of the buttons melted. The steel chain of his gold watch was blended with the gold. His flesh on the right side was scorched and torn, and his metal sleeve-button, and his penknife, and a key in his pocket, were partly fused.

Every pane in the window was smashed, and so completely removed, that it did not appear there had been any glass in it, but the frame was little damaged. A pier-glass, and the room-door were shattered in pieces, and the bed-posts in an adjoining room and the bell-wires were destroyed.

In the room below were the coachman, butler, and footman. The coachman was struck dead. His clothes, his wig, and cravat, were much torn, and the enamel face of his watch broken, and the links of the steel chain fixed together.

The footman was also thrown dead on the floor. He was much scorched and bruised, and had a very large wound in his side. His buckskin breeches were much torn, and the steel of a knee-buckle driven through them. The window-sash was driven in.

The butler had a telescope in his hand, which was broken to pieces, and his hat and wig were thrown to some distance, but he was little injured.

A young lady and her maid were in the room over Mr. Adair, and were thrown down and rendered insensible, and the bed-posts and bell-wires were destroyed.

Multitudes on the shore saw the stream or ball strike the house, and resembled it to a sky-rocket.

Account of the Harmattan, a singular African Wind. By Dr. DOBSON.[1781.]

THE harmattan is a periodical wind, which blows from the interior parts of Africa towards the Atlantic Ocean. It pre

vails, at periods, in December, January, and February, over a line of 2000 miles of coast, and comes from the north-east. It is accompanied by a fog, which leaves a dry whiteness, and affords no dew or moisture. It destroys all vegetation, and renders every thing so dry, that the natives then set fire to the high grass to clear the country, and the destruction spreads with frightful rapidity.

The covers of books, and even of a trunk, are shrivelled up. Household furniture is much damaged, and the panels of doors and wainscot are split. The joints of floors open, and ships become leaky. Casks let out their contents, and require constant attention to their hoops.

The eyes, nostrils, lips, and mouth, are rendered dry and uneasy, and the scurf-skin peels off. Salt of tartar remains dry by day and night, and when previously liquefied becomes dry in two or three hours. The evaporation of all moisture is excessive, or four times that in other countries.

Nevertheless it is salubrious to the human constitution. It recovers invalids in many disorders, and stops the progress of epidemics. It is supposed to proceed from some mountains called Caphas, and to be loaded with the arid pulverised dust of the great desert of Sahara. The south-west wind in the Mediterranean, called the Sirocco, is believed to have the same origin. The Fantees, or black natives, divide the year into the names of the prevailing winds, which they call by the names of the stars.

Account of the Termites in Africa, and other hot Climates. By Mr. H. SMEATHMAN.-[1781.]

THESE ants are called bugga-bugs, wood-lice, white ants, cutters, piecers, eaters, and destructors, in different places. They destroy all timber in buildings, all furniture, and all household stuff and merchandise, and nothing escapes them but metal or stone.

They are called ants, but they do not resemble them in form or changes, only in their large communities and extraordinary nests, constructed with covered galleries, and in their provident labours; but they far surpass our European ants, as well as bees, wasps, beavers, and other animals, in the arts of building, and in sagacity and government.

Their communities consist of one male and one female, who are the common parents of three orders of the insects, which together constitute great commonwealths or monarchies. There are several species, and some build on the ground,

others on the branches of trees, often at great heights. The three orders in each community consist of the labourers, the soldiers, and the winged or perfect insects, which are male and female. From among these latter, kings and queens are elected, which soon emigrate, and found new communities.

The largest species is called termes bellicosus, and is best known on the coast of Africa. It erects immense buildings of well attempered clay, with such art and ingenuity as to excite the astonishment of man. In Senegal they resemble the villages of the natives, being 10 or 12 feet above the ground, and like very large hay-cocks. Comparing the size of the animal with that of man, these buildings are four or five times the height of the Monument.

Every building consists of two parts, an exterior dome, and an interior, divided into an amazing number of apartments. The exterior is a protection from the weather, and in the interior reside the king and queen, and the whole community, with magazines stored with provisions and conveniences.

They raise these immense structures in separate turrets, of the shape and size of sugar-loaves, and then fill it between till the dome is completed, by joining the tops of the lofty turrets, which they raise in the centre. Then they take away the bases of the central turrets, and apply the clay to the construction of the interior. The wild bulls stand on them as sentries for the rest of the herd, and men climb up them when they desire to take distant views, and three or four men may stand on a single one.

oven.

The royal chamber is in the centre, in the shape of a large Its floor is perfectly horizontal, and its roof a solid and well-turned oval arch. The entrances into it are so small, that the king and queen can never leave it. Around it are numerous apartments for soldiers and attendants, and adjoining are magazines filled with gums and hardened juices of plants of various colours. Among these are the nurseries for eggs and young, built of wood joined by gum, and in vast numbers not more than half an inch in width. At first the nurseries are close to the royal chamber; but as the colony increases, those for attendants are increased, and the nurseries placed at greater distances, in performing which they are continually employed. The whole of the central part is covered with a common roof,

Beneath the whole are common sewers of vast size, even as large as the bore of a cannon, to carry off water, and lined with thick clay: one of them, which was measured, was 13 inches in diameter, descending to the gravel, from the finer parts of