INDIRECT BENEFITS DERIVED FROM INSECTS. 241 



again covered with the cloth ; and over it he held the light, 

 which was soon concealed by a layer of these flies, that might 

 have been taken by handfuls from the candlestick. 



But the scene round the tub was nothing to be compared 

 with the wonderful spectacle exhibited on the banks of the 

 river. The exclamations of his gardener drew the illustrious 

 naturalist thither ; and such a sight he had never witnessed, 

 and could scarcely find w^ords to describe. The myriads 

 of Ephemerae," says he, " which filled the air over the current 

 of the river, and over the bank on which I stood, are neither 

 to be expressed nor conceived. When the snow falls with 

 the largest flakes, and with the least interval between them, 

 the air is not so fidl of them as that which surrounded us 

 was of Ephemera?. Scarcely had I remained in one place a 

 few minutes, when the step on which I stood was quite con- 

 cealed with a layer of them from two to four inches in depth. 

 Near the lowest step a surface of water of five or six feet 

 dimensions every way was entirely and thickly covered by 

 them ; and what the current carried off was continually 

 replaced. Many times I was obliged to abandon my station, 

 not being able to bear the shower of Ephemerae, which, falling 

 with an obliquity less constant than that of an ordinary 

 shower, struck continually, and in a manner extremely un- 

 comfortable, every part of my face — eyes, mouth, and 

 nostrils were filled with them." To hold the flambeau on 

 this occasion was no pleasant oflice. The person who filled 

 it had his clothes covered in a few moments with these flies, 

 which came from all parts to overwhelm him. Before ten 

 o'clock this interesting spectacle had vanished. It was re- 

 newed for some nights afterwards, but the flies were never in 

 such prodigious numbers. The fishermen allow only three 

 successive days for the great fall of the manna ; but a few 

 flies appear both before and after, their number increasing in 

 one case, in the other diminishing. Whatever be the tem- 

 perature of the atmosphere, whether it be cold or hot, these 

 flies invariably appear at the same hour in the evening, that is, 

 between a quarter and half-past eight ; towards nine they 

 begin to fill the air; in the following half hour they are in 

 the greatest numbers ; and at ten there are scarcely any to 



VOL. I. R 



