436 Mr. E. L. Garbett's Desanption of some Parhelia 



the scene of the phoenomenon ; but it will of course be under- 

 stood that each spectator saw only his own halos and parhelia, 

 as each one sees only his own rainbow. 



Having no means of angular measurement, I cannot be 

 certain that the pole of this large circle was exactly in the 

 zenith, but it appeared to be so ; and in that case, as it always 

 passed through the sun, its diameter would necessarily vary 

 with his altitude, and would be about 102° when I first saw 

 it, and 98° when it vanished. The width of this band seemed 

 no greater than the sun's diameter, or half a degree, its upper 

 and lower edges being well-defined, though there was a faint 

 light diffused beyond them, as if the intensity throughout the 

 whole width of the band varied something like the ordinates 

 of such a curve as A (fig. 4), where it is plain that, at the two 

 points of contrary flexure, the rapid change of intensity would 

 give the effect of sharply defined edges, though the light con- 

 tinued to diminish beyond them, making the whole breadth 

 of the band perhaps 1^° or 2°; but the width of the conspi- 

 cuous central part was only equal to the sun's diameter. 



There was no trace of colour in this band, and its absolute 

 brightness might possibly have been equal throughout its 

 whole circuit; but this could not be estimated; for owing to 

 the varying contrast afforded by the background of sky, the 

 band necessarily apiieared to grow more and more distinct as 

 it receded from the glare of the sun, till, on the opposite or 

 N.N.W. side, it stood out in bold relief from the bluest part 

 of the sky, and it was difficult not to refer this to a gradation 

 in the intensity of the luminous band itself. 



The two curves of largest radius in fig. 1 represent two 

 other luminous bands which were much fainter, and accord- 

 ingly disappeared much sooner than any other j)artof the phas- 

 nomenon. These bands diverged from the sun, passed over- 

 head as in Plate IV. fig. 2, and met again at the opposite point of 

 the large white circle, where, by their intersection with it, they 

 formed a knot of nebulous light, rather brighter perhaps than 

 would have resulted from the mere crossing of the three lu- 

 minous bands, but hardly bright or definite enough to deserve 

 the name of a mock-sun. The two arcs last mentioned were 

 most distinct where they approached the zenith : and here 

 their distance apart seemed to the naked eye about three- 

 fifths of the diameter of the large circle, or about 60°. From 

 these points they diminished in brightness each way, quickly 

 as they approached the sun, but more slowly as they ap- 

 proached their other intersection, below which they could still 

 be traced ibr a few degrees, while, on the other hand, they 

 could not be traced below the sun. These bands seemed 



