186 
HAL 
of public refort; that we invert God himfelf with them, 
and that we fever them from common ufes. Hooker. 
God from -work 
Now refting, blefs’d and hallow'd the feventh day. Milton. 
'To reverence as holy ,—Hallowed be thy name. Lord’sPrayer. 
HAL'LOWELL, a flourifhing port-town of the Ame- 
can States, 'in the diftriCt of Maine, and the fhire-town 
of Lincoln county, fituated in lat. 44. 16. N. at the head 
of the tide-waters on the yveft fide of Kennebe'ck river. 
An academy is eftablifhed here with a confiderable fund 
in lands. The court-houfe is twelve miles fouth-by-well 
of Vaffalborough, thirty north-by-weft ofWifcaffet, forty 
north-eaft of New Gloucefter, and 195 north-by-eaft of 
Bofton. Hallowell-kook lies on the lame fide of the ri¬ 
ver, three miles below the town, and five north of Pitt- 
fton. The whole townlhip contains A194 inhabitants. 
HALL'STATT, a to\yn of Germany, in the circle of 
Franconia, and bilhopric of Bamberg, fituated near the 
conflux of the Maine, and the Rednitz : three miles 
jhorth of Bamberg. 
HALL'STATT, a town of Germany, in the arch T 
duchy of Auftria, fituated on the lake Hallftatter, with 
afalt-mine near it: twenty-five miles fouth of Gemunden. 
HALL'STATTER SEE, a lake of Germany, in the 
archduchy of, Auftria : fix miles fouth of Gemunden. 
To HALLU'CINATE, v. n. \_hallux , Lat. the great 
toe.] To miftake ; to blunder. Not ufed. 
HALLUCINATION,/, ihallucinalio, Lat.] Error; 
blunder; miftake; folly.—A wafting of flefh, without 
caufe, is frequently termed a bewitching difeafe ; but 
queftionlefs a mere hallucination of the vulgar. Harvey. 
HALLUI'N, a town of France, in the department of 
the Oife, and chief place of a canton, in the diftriCt of , 
Breteuil: ten miles fouth-eaft of Breteuil. 
HALM,/ [healm, Sax.] Straw ; pronounced hawm, 
which fee. 
HALM,/, in botany. See Arundo. 
HALM'STADT, a fea-port town of Sweden, in the 
province of Halland, fituated at the mouth of the Niffa. 
In the year 1327, it was made the capital of the pro¬ 
vince, with fuitable privileges. Here are flourifhing 
woollen manufactures, and a rich falmon fifhery. The 
fortifications are deftroyed. It is ninety-fix miles weft- 
north-weft of Carlfcrona. Lat. 56. 38. N. Ion. 12. 14. E. 
Greenwich. 
HALMYDES'SUS, in ancient geography, a town of 
Thrace. Mela. 
HALMYRO'DES, / [from ccK^vqoq, Gr. Lilted.] A 
medical term frequently applied to the humours, mean¬ 
ing acrimonious. It is alio an epithet of fevers which 
communicate fuch an itching fenfation as is perceived 
from handling fait fubftances. 
HAL'N A, a town of Sweden, - in the province of Weft 
Gothland: feventy-ni.ne miles eaft-north-eaft of Udde- 
valla. 
HA'LO,/. [from eiXut;, Gr. an area or circle.] The 
areola round the nipples. 
HA'LO, or Corona,/ In optics, a coloured circle 
appearing round the body of the fun, moon, or any of 
the larger/tars. Naturalifts conceive the halo to arife 
from a refraCtion of the rays of light in palling through 
the fine “rare veficulte of a thin vapour towa'rds the top 
of the atmofphere. Various hypothefes have been-fug- 
gelled by different aftronomers-to account for this phe¬ 
nomenon. Des Cartes infills, that a halo never appears 
when it rains; whence he concludes that it is wholly 
occafioned by the refraCtion of light in round particles 
of ice then floating in the atmofphere; and to the,dif¬ 
ferent protuberance'of thefe particlgs he afcribes the 
variation in the diameter of the halo. Galfendi fup- 
, pofes, that a halo is occafioned in'the Tame manner as 
fhe rainbow ; the rays of light being, in both cafes, 
twice refradled'and once refledted within each drop of 
rain or vapour, and that the difference between them is 
HAL 
wholly owing to their different fituation with refpedt to 
the obferver. Dechales alfo endeavours to fhew that 
the generation of the halo is fimilar to that of the rain¬ 
bow ; and that the reafon why the colours of the halo 
are more dilute than thofe of the rainbow, is owing 
chiefly to their being-formed', not in large drops of raiti, 1 
but in very final! vapour. I]ut the moll generally re¬ 
ceived opinion relating to the generation of halos, is that 
of Mr. Huygens, who imagines halos, or circles round 
the fun, to be formed by fmall round grains of hail, 
compofed of two different parts, the one of which is 
tranfparent, inclofing the other, which is opaque ; which 
is the general (trudture adtually obferved in hail. He 
farther fuppofes that the grains or globules which form 
thefe halos, confifted at firft of foft fnow, and that they 
have been rounded by a continual agitation in the air, 
and thawed on their outfide by the heat of the fun ; and 
he iliuftrates his ideas of their formation by geometri¬ 
cal figures. Weidler, however, endeavours to refute 
Huygens’s theory of halos, by fuppofing a vaft number 
of fmall vapours, each with a fnowy nucleus, coated 
-round with a tranfparent covering. He fays, that w.hen 
the fun paints its image in the atmofphere, and by the 
force of its rays puts the vapours in motion, and drives 
them toward the furface, till they are collected in fuch 
a quantity, and at fuch a diftance from the fun oh each 
fide, that its rays ai;e twice refraCted, and twice reflect¬ 
ed, when they reach the eye they exhibit the appear¬ 
ance of a halo, adorned with the colours of the rainbow ;• 
which may happen in globular pellucid vapo'urs with¬ 
out fnowy nuclei, as appears by the experiment of hol¬ 
low fpheres of glafs filled with water; therefore, when¬ 
ever thofe fpherical vapours are fituated as before-men¬ 
tioned, the refractions and reflections will happen every 
where alike, and the figure of a circle, with the ufual 
order of colours, will be the confequence. 
Newton has laid down his theory of halos in his Optics, 
p. 155 ; and his theory was confirmed by aClital obferva- 
tion in June 1692, when the author faw by reflection, in 
a velfel ofstagnated water, three halos, or rings of co¬ 
lours, about the fun, like three little rainbows concen¬ 
tric to his. body. Thefe coronas inclofed One another 
immediately, fo that their colours proceeded in this . 
continual order from the fun outward: blue, white, 
red; purple, blue, green, pale yellow, and red ; pale 
blue, pale red. Similar halos fOmetim'es appear about 
the moon. The more equal the'globules of water or 
ice are to one another, the more circles of colours will 
appear, and the colours will be the more lively. 
On the r8th of February, 1796,-after a. mild day, in 
an evening not very clear, the moon Alining bright, a 
large and a fmall halo were obferved found the moon, 
by W. Hall, efq. at his refidence, near Berwick. The 
diameter of the larger one fubtended an angle of 112 0 , 
that of the fmall one was under'12 0 and more than 8°. 
Mr. Hall concludes by remarking :—“ This halo appears 
fomewhat to refemble the famous one of the fun, ob¬ 
ferved at Rome in 1629, and defcribed by Scheiner; it 
therefore deferves the more attention, efpecially as the 
great halo, on the prefent occafion, having its fouth- 
weftern limb elevated to the height of 54 0 , and its north- 
eaftern deprefled to within 14 0 of the horizon, was in an 
oblique pofition, not eafily reconciled with the theory 
ofj Huygens, which feems to,require that fuch circles 
fliould be equally elevated above the horizon all round. 
It alio fh'ews, that Scheiner’s original plan of the halo 
at Rome, which reprefented it as oblique* may have 
been right; and that Huygens’s correction, which makes 
it parallel to, the horizon, was probably an erroneous 
conjecture.” 
On the 30th of November 1786, the Rev. James Wood, 
A.M. fellow of ,St. John’s college, Cambridge, obferved 
three very brilliant halos round the moon. The order 
of the colours, beginning from the moon, was, white of 
a confiderable breadth, yellow, orange, red ; violet, 
green. 
