968 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



insects of perfect organization and in full activity. They were a 

 kind of water-flea, with branched horns, called by Swanimerdam 

 Pidices arborescentes, but how they became so suddenly multi- 

 plied has never been explained. Something analogous to this 

 occurred at Greenvrich a few years ago. During a very gloomy 

 rain a universal deposit of small black flies took place, and in 

 some instances plants were completely hid from view. About 

 eleven ycai's ago a similar deposit was noticed at Cambridge, 

 England. On the 14th of March, 1813, the inhabitants of Gerace, 

 Calabria, were greatly alarmed by a thunder storm during which 

 they saw large drops of red rain. In another part of Italy colored 

 ruin fell under similar circumstances. Sementini analyzed a por- 

 tion of it, and found that the coloring matter consisted of light 

 dust of a marked earthy taste, which under heat became brown, 

 then black, and finally red. It consisted principally of silica, 

 alumina, lime, carbonic acid, oxyde of iron, and a yellow, resinous 

 substance. It is very probable that these and similar specimens 

 of colored dust were first emitted from an active volcano. After 

 being carried a consideraljle distance through the upper regions 

 of the atmosphere, they finally descended in the form of rain. A 

 shower occurred at Oneglia, Piedmont, on the 27th of October, 

 1814, which left on trees and grass the appearance of blood spots. 

 Messrs. Mayer and Stook, chemists, of Bruges, analyzed some of 

 the colored matter which fell during a shower in 1819, and found 

 it was principality chloride of cobalt. Prof. Giuli sulyected to 

 aualj'Sis a deposit on the leaves of the plants in the Botanical 

 Garden at Siena, Tuscany, and found it to be composed of some 

 veo'etable oro-anism in combination with several oxides and carbon- 

 ates. The deposit after a remarkable rain on the 19th of Feb- 

 ruary, 1819, in the district between Genoa and the Lago Maggiore, 

 consisted of talc, cjuartz, carbonate of lime, bituminous matter, 

 and remains of seeds of different plants. On the 9th of Novem- 

 ber, 18'19, the city of Montreal, Canada, was suddenly enveloped 

 in darkness, when rain as black as ink began to fall. Some of this 

 liquid .Avas sent to New York for analysis, and the coloring matter 

 was found to consist simply of soot. Its origin was doubtless a 

 great fire in the forests of Ohio ; during its progress the wind 

 blew steadily towards the north. Similar black rains have been 

 reported in the United States. In Scotland they have been fre- 

 quently noticed. A remarkable rain occurred on the 24th of 

 April, 1781, in the island of Sicily. The water, on evaporating, 



