148 Scientific Notices-^Mineratogi/* [Feb.- 



place, but a German word meaning cube ore. The mineral 

 occurs in Cornwall, had been analyzed before by Chenevix and 

 Vauquelin, and has been long known to British mineralogists. 

 It is also, according to Berzehus, a compound salt, and its con- 

 stituents are, 



1 atom subsesquarseniate of protoxide of iron, 



2 atoms subsesquarseniate of peroxide of iron, 

 18 atoms water. 



I do not give the numbers corresponding to these atoms, 

 because the opinion which Berzelius entertains respecting the 

 composition of arsenic acid, and which doubtless influenced his 

 analysis, is not the same as mine. 



I may mention that the mineral called mesela in the notice 

 ■which you have inserted in the Annals, is called Mesolin by 

 Berzelius, in his new mineralogical arrangement printed in the 

 Memoirs of the Swedish Academy for 1824. 



I am, &c. Thomas Thomson. 



4. Fall of Aerolites, 



On the 15th of January, 1824, between nine and ten o'clock 

 in the evening, a fall of aerolites happened in the lower part of 

 the Commune of Renalzo, distant 21 miles from the town of 

 Cento, in the province of Ferrara. This phaenomenon was pre- 

 ceded by the appearance of a bright hght, which terminated in 

 flashes of lightning. Next were heard, for some miles around, 

 three loud explosions, like discharges of artillery, which were 

 immediately followed by a noise similar to the firing of musquetry, 

 and was distinctly audible as far as the town of Cento. In a 

 short time this noise changed to a sound like that of a number 

 of bells ringing all at once. At last some-~stones fell with 

 violence, accompanied by a whistling noise, and notwithstand- 

 ng the darkness of the night, the direction of their fall could be 

 determined, which led to the discovery of the stones themselves. 

 It is said that three of these aerolites have been found. The 

 phaenomenon lasted about 20 minutes. The stones were found 

 at an interval of about a mile asunder. Some persons speak of 

 a black cloud which at first appeared in the south-east, from 

 whence it took an oblique direction towards a black body, appa- 

 rently of the size of a common cauldron, and at length becommg 

 luminous, presented to the eye and ear the phaenomena above 

 described. Prof. Ranzani possesses one of the aerolites, which 

 is said to weigh about a pound and a half. They are blackish ; 

 externally their colour is lighter, and internally they are sprinkled 

 with brilliant points of the colour of iron, with globules of the 

 same colour still more brilhant, and with small, whitish, round 

 corpuscles, with indeterminate facets, and varying in diameter 

 from one-sixteenth of a line to a line. Further particulars are 



