Oct. 24, 1884.] 



KNOWLEDGE ♦ 



335 



and it is delightfully refreshing to place oneself for a 

 time in conimunication -with these great spirits of old and 

 try to see things with the eyes with which they saw them. 

 The renowned French naturalist, Reaumur, gives a most 

 minute and graphic account of the first swarm of May-flies 

 he witnessed, aid the details are so remarkable that they 

 are worthy of rt capitulation, if for the thousandth time. It 

 was in the year 1738 that the experience occurred to him. 

 His garden was situated on the bai ks of the Marne, and 

 on August 19 a fisherman informed him that on the 

 previous day ihc flies had begun to appear along the river; 

 or, as he expiessed it, the " manna had begun to fall" — a 

 metajihor commonly used to express the advent of the 

 swarms. The illustrious naturalist, therefore, being deter- 

 mined to have a near view of the hatching of the 

 creatures, gi t into a boat about three hours before sunset, 

 and, proceeding down the river, detached from the banks 

 great masses of earth which contained abundance of 

 pupre, transferring them to a tub of water he had taken 

 with him. Having stayed out till about eight o'clock, 

 intently watching both banks and tub, but without seeing 

 very many flies, he bethought him that, as a storm seemed 

 to be brewing, terra firma would be preferable to an open 

 boat. He therefore landed, and had the tub conveyed into 

 his garden. But just at thi.s moment the insects began 

 to emerge from the tub in vast numbers, crowding up 

 from the water on to every exposed piece of earth, in order 

 to shed their skins and put on their wings. The scene 

 must have been a most entertaining one ; but, in the midst 

 of it all, the rain came on so severely that the observer, 

 ardent as he was, was obliged to beat a retreat, not, how- 

 ever, before covering up the tub with a cloth, that he might 

 not lose his precious insects. The storm soon abated, and he 

 again visited the tub, when he found the crowd of insects 

 much increased, many of them having been drowned through 

 their inability to find .sufficient standing loom under the 

 cloth. By this time it was quite dark, so that the obser- 

 vations had to be conducted by torchlight ; but the light 

 proved a strong attraction to the multitudes of flies that 

 were now emerging from the river, and they flocked 

 round in such numbers that they roon completely covered 

 the cloth which had again been thrown over the tub, and 

 might even have been taken up in handfuls. The delighted 

 naturalist and his attendants now made their way to the 

 river, and here the spectacle was far more astonishing, 

 for, as he says, " the myriads of ephemera which filled 

 the air over the current of the river and over the bank 

 on which I stood are neither to be expressed nor con- 

 ceived. When the snow falls with the largest flakes, 

 and with least interval between them, the air is 

 not so full of them as that which surrounded me 

 was full of ephemer.T. Scarcely had I remained in 

 one place a few minutes, when the step on which 

 I stood was quite concealed with a layer of them 

 from two to four inches in depth. Many times I was 

 obliged to abandon my station, not being able to bear the 

 shower of ephemera?, which, falling with an obliquity less 

 constant than that of an ordinary shower, struck con- 

 tinually, and in a manner extremely uncomfortable, every 

 part of my face. Eyes, mouth, and nostrils were filled with 

 them." Multitudes, of course, were drowned, but as fast 

 as the stream carried them away, new ones were ready to 

 take their place. The swarms continually increased in 

 density till between 9 and 9.30, when they reached their 

 maximum ; but in the succeeding half-hour their numbers 

 rapidly diminished, and by ten o'clock the marvellous 

 spectacle had completely vanished ; the vast hosts that 

 had filled the air so short a time before, having ful- 

 filled their destiny, were now numbered with the dead. 



Other batches came forth some nights afterwards, bnt not 

 again in such enormous numbers. The fishermen reckon 

 three successive days for the greatest " fall of the manna," 

 and during this time, of course, the fish hold a grand 

 carnival, gorging themselves on the delicate morsels as they 

 fall into the river. 



It is remarkable that in Ceylon there is a species of 

 May-fly the abdomen of which is luminous — sutficiently so, 

 indeed, to enable one to capture the insect, even on a very 

 dark night. 



(To he continued.) 



I 



OTHER WORLDS THAN OURS. 



A WEEK'S CONVEESATION ON THE PLUEALITY OW 

 WORLDS. 



By Mons. de Fontenelle. 



with notes by richard a, proctoe. 



THE THIRD EVENING.— PARTICULARS OF THE WORLD 

 IN THE MOON, AND PROOFS OF THE OTHER 

 PLANETS BEING HABITABLE. 



( Continued from p. 301.) 



SHOULD rejoice," says the Marchioness, " at a 

 wreck of these lunar folks, as much as my neigh- 

 bours on the coast of Sussex. How pleasant would it be 

 to see 'em lie scattered on the ground, where we might 

 consider at our ease their extraordinary figures." 



" But what," said I, " if they should swim on the out- 

 ward surface of our air, and be as curious to see us, as jon 

 are to see them ; should they angle or cast a net for us as 

 for so many fishes, would that please you 1 " 



" Why not," said the Marchioness, smiling. " For my 

 part, I would go into their nets of my own accord, were it 

 but for the pleasure of seeing such strange fishermen." 



" You would be very sick," said I, " when yon were 

 drawn to the top of our air ; for there is no respiration in 

 all its extent, as may be seen on the tops of some very hjgh 

 mountains ; and I admire, that they who have the folly to 

 believe that fairies, whom they allow to be corporeal, and 

 to inhabit the most pure and refin'd air, do not tell us that 

 the reason why they give us such short and seldom visits 

 is, that there are very few among them that can dire ; 

 and those that can, if it be possible to get through the 

 thick air where we are, cannot stay half so long in it as 

 one of your diving fowls can in the water. Here, then, 

 are natural barricades, which defend the passage out of 

 our world as well as the entry into that of the moon ; so 

 that, since we can only guess at that world, let us fancy all 

 we can of it. For example, I will suppose that we may 

 there see the firmament, the sun, and the stars of another 

 colour than what they are here. All these appear to us 

 tliro' a kind of natural opticks, which change and alter the 

 objects. These spectacles, as we may call 'em, are our air, 

 mix'd as it is with vapours and exhalations, and which 

 does not extend itself very high. Some of our modern 

 philosophers pretend of itself it is blue, as well as the 

 water of the sea, and that this colour neither appears in 

 the one nor in the other but at a great depth. The firma- 

 ment, say they, where the fix'd stars are placed, has no 

 peculiar light of its own, and by consequence must appear 

 black, but we see it through the air, which is blue, and 

 therefore it appears to us blue ; which, if so, the beams of 

 the sun and stars cunnot pass thro' the air without being 

 tirg'd a little wiih its colour, and losing as much of their 



