VOL. XL.] PHILOSOPHICAL TRANSACTIONS. 137 



than that: its light was white; its figure round, audits size equal to that of 

 the sun s. This parhelion a shot out the stream il, which was rectlinear, 

 white and resplendent, 8° long, and void of colours ; and it lasted somewhat 

 longer than the former, without changing its figure. On the sun's being hid 

 by thick clouds, about 4- hour after eleven, both these mock-suns disappeared ; 

 but they became visible again, on the sun's shining bright. 



The whole of the phaenomena observed in these parhelia comes to this : 

 that the true sun, s, was accompanied by two parhelia, both 20° distant from 

 the sun, one on each side, and having nearly the same altitude with the sun 

 from the horizon. Above the parhelia, part of a rainbow surrounded the 

 zenith; and each of the parhelia sent forth a bright luminous strean) or tail, 

 one rectilinear and white, the other soraewliat curved and coloured. More- 

 over, from the western parhelion, a stream parallel to the horizon, and some- 

 what pointed, extended itself on the side opposite to the sun ; and this scene 

 lasted the 2 hours of 10 and 1 1 before noon, till thick clouds put an end to it. 

 There was no appearance of an entire crown, such as usually accompanies 

 parhelia, and encircles the sun. 



An Observation of three Mock-Suns seen in London, Sept. 17, 1736. By 

 Martin Folkes, Esq. F. Pr. R. S. N" 445, p. 59. 



Sept, 17, 1736, as Mr. Folkes was reading a little after 7 in the morning, 

 in a room looking towards the north-east, he accidentally noticed an odd stream 

 of coloured light, shooting upwards from the sun, shining through a thin 

 waterish cloud ; but recollecting the appearance was several degrees more nor- 

 therly than the sun's true place at that time, he went to the window, and found 

 what he had taken for the sun was a parhelion, shooting out a short horizontal 

 stream or tail towards the north ; the sun itself shining pretty bright and clear 

 at the same time. He also observed, that the stream he had at first seen, was 

 part of an arch concentric to the sun, and passing through the parhelion : this 

 arch was for a good way tolerably defined, and tinged with red on the inside, 

 and a bluish white on the other. Casting his eye to the other side the sun, 

 he perceived a second parhelion, at the same distance from him, towards the 

 south, though not yet so bright as the first. He then went up to the leads of 

 his house, where he soon found the phenomenon considerably to improve, the 

 arch round the sun forming itself into more than a semicircle, reaching almost 

 to the horizon northward, and with very little discontinuance beyond the second 

 parhelion towards the south. He then began to perceive a third parhelion, 

 where the circle surrounding the sun would have been cut by the vertical 



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