438 
P AR H I 
PARGO'W, a town of Hindooftan, in the circar of 
Gohnd : nine miles fouth-fouth-weft of Koocfc. 
PAR'HAM, a town of the ifland of Antigua: five 
miles weft of St.John’s. 
JPARHE'LION, f [Greek; formed of impa, near, and 
wAi oq, fun.] A mock-fun, or meteor, being a part of the 
heavens.ftrongly illuminated by the image of the fun, and 
appearing like another fun, but often-coloured and drawn 
out to a confiderable length, in the form of a tail.—To 
negledl that fupreme refplendency, thatfhines in God, for 
thole dim reprefentations of it that we fo dost- on in the 
creature, is as abfurd, as it were for a Perfian to offer flis 
iacrifice to a parhelion, inftead of adoring the fun. Hoyle. 
The apparent lize of parhelia is the fame as that of the 
truefun; but they are not al ways round, noralwaysfobright 
as the fun ; and, when feveral appear, fome are more bright 
than others. They are tinged externally with colours like 
the rainbow, and many of them have a long fiery tail oppo- 
fite to the fun, but paler towards the extremity. Some 
parhelia have been obfervedwith two, and others with three, 
tails. Thefe tails appear for the moft part in a white ho¬ 
rizontal circle, which generally paffes through all the par¬ 
helia ; and, if it were entire, would go through the centre 
of the fun. Sometimes there are arcs of fmaller circles, 
concentric to this, touching thofe coloured circles which 
furroundthe fun. They are alfo tinged with colours, and 
contain other parhelia. Parhelia are generally fituated in 
the interfedlions of circles; but Cafiini fays, that thofe 
which he faw in 1683 were on the outlide of the coloured 
circle, though the tails were in the circle that was parallel 
to the horizon. AEpinus apprehends that parhelia with 
elliptical coronas are more frequent in the northern regions 
and thofe with circular ones in the fouthern. They have 
been vifible for one, two, three, and four, hours together; 
and in North America they are faid to continue fome days, 
and to be vifible from fun-rife to fun-let. When the par¬ 
helia difappear, it fometimes rains, or there falls fnow in 
the form of obiong fpiculas, as Maraldi, Weidler, Kraft’t, 
and others, have obferved ; and, becaufe the air in North 
Americaabounds with fuch frozen fpiculas, which are even 
vifible to the eye, according to Ellis and Middleton, fuch 
particles have been thought to be the caufe of all coronas 
and parhelia. 
Ariftotle obferves, that two were feen in the Bofphorus 
from morning to evening, though, in general, heobferves, 
they are not feen except when the fun is near the horizon. 
Pliny relates under what confuls this phenomenon was 
ever feen at Rome. In the year 1629, was feen at Rome, 
by Scheiner, a parhelion of four funs ; and the fame num¬ 
ber was feen by M. Mufchenbroeck at Utrecht. GafTendi 
lays, that in 1635 and 1636 he often faw one mock fun ; in 
1S61, Heveiius oblerved at Dantzic one offeven funs; and 
in 1666, another w as feen at Arles, of fix. Phenomena of 
this kind have alfo been obferved by M! de la Hire at Paris 
in 1689, and by M. Cafiini in 1693; by Mr. Grey in 17005 
by Halley in 1702 ; and by Maraldi in 1721. 
Ariftotle (Meteor, cap 3.) was ofopinion, that rainbows, 
halos, and mock funs,were all occafioried by the refiedlion 
oftlie fun-beams in different circumftances, by which an 
imperfect image of his body was produced, the colour only 
being exibited, and not his proper figure. The image, 
he fays, is not fingle, as in a mirror; for each drop of rain 
is too fmall to reflect a vifible image; but the conjunction 
of all the images is vifible. 
M. Mariotte accounts for the appearance of parhelia 
from an infinity of little particles of ice floating in the air, 
which multiply the image of the fun, either by refra&ing 
of breaking his rays, and thus making him appear where 
he is not; or by reflecting them, and fervingas mirrors. 
The known laws of reflection and refraCtion have given a 
handle for geometrizing on thefe phenomena; and M. 
Mariotte has determined the precife figure of the little 
icicles, and theirfituation in the air, thefize of the coronce, 
or circles, which accompany the parhelia, and the colours 
with which they are painted, by a geometrical calculus. 
The hypothefis of Defcartes, to account for that hori- 
L I O N. 
zontal circle in which mock funs appear, has lefs proba¬ 
bility than any of his conjectures. He fuppofes that a 
great quantity of frozen vapours, crouded together by 
contrary winds, form a prodigious cylinder, which reflects 
the light that falls from it on all tides, fo as to exhibit 
that lucid appearance in all the furrounding clouds. M. 
Huygens, on applying his attention to thefe appearances* 
was foon fenfiiffe that they could not arife from fuch 
globules as formed the halos; yet, fince parhelia are al¬ 
ways attended with halos, he was fatisfied that their caufe* 
muff be much alike. Conlidering, then, what other 
figures hail-ftones might poflibly have befides a fpherical 
one, he could find no other fo Ample as that of a cylinder; 
and, indeed, he had often obferved, that fnow did confifi 
of feveral {lender oblong particles, mixed with thofe of 
other thapes^ and feeing that fmall globules were fufiicient 
for the production of halos, he imagined that a great 
number of fmall cylinders, floating in the air, might pro¬ 
duce fimilar appearances. He alfo remembered that 
Defcartes had taken notice of certain fmall columns, or 
cylinders, which he had feen lying on the ground, the 
extremities of which were bounded with flat liars, confift- 
ing of fix rays or points. 
The large and white horizontal circle, in the Roman 
phenomenon, M. Huygens fuppofed to be produced by 
the reflection of the fun’s rays from the outfides of the 
upright cylinders; fince, when the fun thines upon a 
great number of fuch cylinders fufpended in the air, a 
white circle mull neceffarily appear to pafs through the 
fun, parallel to the horizon, and of the fame breadth with 
that of the fun. This he (hows very diftinCtly by a large 
figure of a cylinder, and by pointing out the progrefs of 
the fun’s- rays reflected from it: for every point of the 
fun’s vertical diameter, as well as his centre, will illu¬ 
minate a circle of cylinders, of the fame apparent height 
as the illuminating point. It is obfervable that no thick 
clouds are feen in the air when thefe circles appear, but 
only fuch as are very thin, and fcarcely vifible: for, in 
moil of thefe ohfervations, the fky is faid to have been very 
clear and ferene, which very well agrees with this hypo¬ 
thefis ; fince thefe minute cylinders mud conllitute a very 
thin cloud uniformly extended ; through which the fun, 
and even the blue colour of the fky, may be feen. 
He then proceeds to demonllrate his hypothefis, by an 
accurate confideration of the refraClion of the rays of 
light through the tides of fuch cylinders as have been 
deferibed ; and he invelligates the diftance at which the 
parhelia mull appear from the fun ; thowing that it is fo 
much the greater, as the internal cylinderof fnow is thick¬ 
er in proportion to the whole cylinder; and that this dif¬ 
tance mull become greater as the fun riles higher; and he 
fubjoins a table of thefe diftances, in proportion to any 
given altitude of the fun ; from which it appears, that if 
a fufiicient number of cylinders be placed oneabove ano¬ 
ther, (fome of which are melted more and fome lefs,) be¬ 
fides the collateral parhelia next the fun, two or more 
may appear farther from him, but ftill in the fame white 
circle ; which was alfo confirmed by the ohfervations of 
Heveiius in 1661, and of Scheiner in 1630. It appears 
alfo, from the fame tables, that, while the cylinders remain 
in the fame fituation, as the fun rifes higher the intervals 
between him and the two parhelia will increafe, which 
was the very thing that he himfelf had obferved. But 
a greater alteration of thefe intervals may happen, if the 
cylinders be more melted ; and from hence might arife 
that very remarkable phenomenon, which is faid to have 
appeared in the time of Augullus, when three funs were 
feen at the fame time, all of which were foon contradied 
into one ; which, he obferves, would be effected by the 
warmth of the air melting the fnow in the cylinders ; by 
which means both the parhelia would draw nearer to the 
fun, till they coincided with it; at which time all the cy¬ 
linders would be melted, and changed into round drops. 
M. Mufchenbroeck fays, that nothing has been ad¬ 
vanced concerning the caufe of parhelia, more probable than 
the hypothefis of M. Huygens, except that frozen cylin- 
3 ders 
