614 
Halo. for want of raatter, or of a due disposition. For in the 
—\——"_ vertical:circle I I 2 
Piers for a long time. . I saw also very manifest reciproca- 
CCLXXXVIT tong of the lateral parhelia, The iris ORP seems to 
Sidi have been a portion of a single circle concentric to the 
sun, but towards x and @ it did not quite touch the ho- 
rizon AB; and the lengths of the arches O x, P 6 were 
variable. The arches ZQa, 8Qy, 3¢@, that imme- 
diately surrounded the sun, seemed to the eye to com- 
ose a single circumference, but it was confused, and 
had unequal breadths ; nor did it constantly continue 
like itself, but was perpetually fluctuating. But in 
reality.it consisted of the arches expressed in the scheme, 
-as L accurately observed for that very purpose. The 
horns HRC seemed to be a portion of a smaller circle 
‘touching the greater ORP in a contrary position in a 
common knot at R. The arches cut each other in a 
knot at Q, and there they formed a parhelion. The 
arhelia N, M sprung out from the common intersections 
Mf, N of the iris 32, and of the whitish circle ONMP. 
‘The north part of the sky was clearer than the south, 
which, being overcast with slender vapours, afforded 
more matter for this appearance.” See Gassendi’s Ope- 
ra, tom. vi. p. 401. 
Paraselene — Hevelius observed the following paraselenz at Dant- 
nak byHe- zie en the 80th March 1660. “ In the beginning, at 
nen: "one o'clock in the morning, the moon’A was surround- 
ed by an entire whitish circle BCDE, in which there 
PLATE were two mock moons at B and D,-one ateach side of 
‘©CLXXXvII the moon, consisting of various colours, and shootin, 
Pig. 4, out very long and whitish beams by fits. That on the 
left hand extended its tail towards the thigh of Serpen- 
tarius, the other on the right extended its tail toward 
Jupiter, as represented in the Figure. Afterwards, at 
two o'clock, a larger circle surrounded the lesser, and 
reached down to the horizon. The tops of both these 
circles were touched by coloured arches like inverted 
rainbows, The inferior arch at C was a portion of a 
larger cirele, and the superior a portion of a lesser, 
This extraordinary sight lasted near three hours; the 
outward great circle vanished first of all, then the lar- 
ger inverted arch at C, and presently the lesser, and, 
last of all, the inner circle BCDE disappeared. The 
diameter of this inner circle, and also of the superior 
arch, was 45 degrees ; that of the exterior circle, and 
inferior arch, was 90 degrees.” 
Parhélia Qn the 6th April 1660 Hevelius observed the par- 
pat by He- helia shewn in Fig. 5. ** At half.an hour past five in 
léco, _—«the-evening, while the sun ‘was descending towards the 
Rie. 5 horizon, he was crowned with arches of circles of va- 
ig. 5. . ’ : 
rious colours like the rainbow. In the corona, en op- 
posite sides of the sun, there were two parhelia va- 
riously coloured with .pretty long and whitish tails 
pointing from the sun. Near the zenith, where the 
corona was a little faint and imperfect, there shone out 
another inverted arch, having a third parhelion in the 
middle of it, which appeared somewhat obscure. This 
phenomenon lasted half an hour till sun-set, the sun 
being very clear. The inverted arch, and the upper 
parhelion, disappeared first ; and then the parhelion on 
the left hand ; but the third parhelion set with the true 
sun, Missing nes of the corona round abont the’sun 
fy was about 45 degrees, as I guessed by my eye.” 
pe nH On the17th December 1660, Hevelins stenid at Dant- 
velius in  2i¢ the following paraselene, which.are shewn in Fig. 6. 
1660. *On-the first day after the full moon,” says he, “at thirty 
Fig. 6. minutes,past six in the morning, themoon being 12°high, 
I saw the moon in the west, 
about her in -this manner. 
first, I observed the moon 
with three mock moons 
The air being very clear at 
surrounded with a double 
HALO. 
saw plainly some sketches of parhelia’ 
corona (near her body, as the e seems to represent 
tin eed very bright and. beautiful colours. On 
each side of the moon there were two arches of a 
circle, about 45 degrees in diameter, which were 
coloured like the rainbow, and ‘extended down to the 
horizon, in which were two mock moons with very long 
white tails. That on the left hand was near on 
with a short tail ; the other on the right hand had a 
longer tail. In the upper part, where these collateral 
soched concurred, there was another arch inverted, and 
variously coloured with a third mock moon in the mid- 
dle of it, and somewhat duller than the other two. 
Moreover, what was very extraordinary, there passed a’ 
large white rectangular cross through the middle of the 
moon, whose lower part reached down to the horizon; 
but on each = it did not quite touch the corona, as 
appears e Figure. It was so very bright and 
ocala tek it dhone distinetly and eldariyill eines ; 
but the mock moons disappeared a little before.” 
In Mathew Paris’s History, the phenomenon seen in Halo seed 
Fig. 7. is thus described: “ A wonderful sight was in 1233, | 
seen in England A. D. 1233, April 8. in the 17th year & 
of the reign of Henry III. and lasted from sun-rise till Px.are 
noon, At the same time, on the 8th of April, about ccixx: 
one o’clock, on the borders of Herefordshire and Wor- Fig 7 
cestershire, besides the true sun, there appeared in the 
sky four mock suns of a red colour ; also a certain large 
circle of the colour of crystal, about two feet broad, 
which encompassed all England as it were. There next 
went semicircles from the side of it, in whose*intersec- 
tions the four mock suns were situated ; the true sun 
being in the east, and the air very clear. And because 
this monstrous prodigy cannot be described by words, 
I have represented it by a scheme that shews imme- 
diately how the heavens were circled. The appearance. 
was painted in this manner by many people for the 
wonderful novelty of it.” 
Figure 8. represents a parhelion observed at Leyden Halo scen 
A. D. 1653, Jan. 14, between one and two o'clock in at Leyd 
the afternoon, in the academical observatory, by Sa- i" 1653. 
muel Char. Kechelius a Hollenstein. « The circle BDC Fig. 3. 
was white, and almost 35’ broad; the altitude of’ its : 
highest point D was 38° 23’. Its centre was in the 
sun, whose height was 15° 48’; that is, at $6’ past 
one, his azimuth being 23° 40’ towards the west, and 
the angle made by his vertical circle and the ecliptic 
60° 54’, The mock suns B, C were oblong and un.’ 
equal, at the distance of 22° 35’ on each side of the 
sun, and had the same altitudes as the sun. ‘The west-' 
ern parhelion at C was the fainter of the two, and’ 
changed from yellow to white, and disappeared first ; 
the eastern one at B was brighter, with a lucid arch 
shooting from the sun, and was coloured with purple, 
red, om yellow ; the shape of its tail BF was conical, 
27° tong, the parhelion«being the base of the cone; 
the part BE, 13° 10’ long, consisted of bright yellow, 
and red light ; the other EF being whitish, which 
vanished before the parhelion did. {t appeared for 
half an hour, and lasted one quarter longer than C ; 
and the corona disappeared a little after.” 
On the 18th May, 1652, Huygens observed a halo, puto seen 
which he thus describes :—“ I observed a circle about’ by Huy.” 
the sun in its centre ; its diameter was about 46°, and gensin 
its breadth the same’as that of a common rain-bow. It !652- 
had also the same colours, though very weak, and scarce 
discernible but in a contrary order, the red being next 
the sun, and the blue being very dilute and whitish. 
All the space within the circle was by a dul- 
ler vapour than the rest of the air; of such a texture 
as to obsoure the sky with a sort of a continued cloud; 
