( I 4)


URAN, in a Medicinal Senfe, i Solution of the Conti-
*uity of a Part of the Body, by the Impreffion of Fire: or
a Mark remaining on the Thing burnt. Of Burns, Phyfi-
cians make feveral Degrees The firic, when there are on-
ly a {few Puflules rais'd on the Skin, with a Rednefs, and
a Separation of the Epiderma fronti the genuine Skin. The
fecond when the Skin is burnt, dried, and fhrunk, but
without any Craet or Scab. The third is, when the Flefh,
Veins, Nerves, LeSc. are lhrunk, and form a Scab. Lzfita-
hus recommends an Unguent, made of the Afhes of Law-
rel Leaves burnt, with Hog's Fat dropp'd on 'em, for a
Burn; or, ion occafion, the Unguent Populeum, with
Vine L'eaves laid over it. Panarole obferves, that Clay
laid on a lBurn abates the Pain; and the Brewers in Rol-
lanad, ufe a Decot ion of Ivy for the Cure of Burns.
Burns, however, are not only Difeafes, but in fome
Cafes Remedies. M. Romberg obferves, that in the Ifle
of _ava, the Natives dure themselves of a Cholick, other-
wife Mortal, by burning the Soles of their Feet; and cure
themselves of a Panaris, by dipping their Finger in boiling
Waterfeveral times. Travellersrelate many other Cafes of
other Difeafes cur'd by burning: And we fee the EIecqs of
it our felves, in Horfes, Hounds, Birds of Prey, Uec. A
kind of Mofs, brought from the Indies, has been likewife
us'd for the Gout; apply'd, by burning it on the Part af-
fe,%ed: and M. Homberg gives us InjRances of two Wo-
men cur'd, the one of a violent Difeafe in the Head and
Eyes, and the other of a Difeafe in the Legs and Thighs,
by the accidental burning of thofe Parts. He adds, that
burning may cure in three manners; either by putting the
peccant Humors into a greater Motion, and making 'em
take new Routs; or by diffolving and breaking their Vif-
cidity, or by deflroying the Canals which brought them in
too great Quantities. See CAUSYie, and CAUITErY.
BURNING, the Aaion of Fire on fome Pabulum or
Fuel, whereby the minute Parts thereof are torn from each
other, put into a violent Motion; and, afluming the
Nature of Fire themselves, fly off in Orbem. See FIRE.
BURNING, or BRENNIN0, in our antient Cuftoms,
was an infeaious Difeafe, got in the Stews, by converfing
with leud Women; fuppos'd to be the fame that we now
call the Venereal Difeafe: Whence that Difeafe is argu'd
to be much more antient than the common Epocha of the
Siege of Natples. See VENEREAL DIsE &sE, and CLAp.
The chief Obje~tion againft YBurning being the fame with
the Venereal Difeafe, Is, that the Remedies prefcrib'd
againfi the former, would be inefifeLual ini the latter: But,
befide that it is not to be expeled, the Meafures of the
antient Phyficians Ihould be calculated for the removing of
any Malignity in the Mafs of Blood or other Juices, as in
the Modern Praffice-; inafmuch as they look'd on the Dif-
eafe as merely local, and the whole of the Cure to depend
on the Removal of the Symptoms: Befides this, it is
matter of frequent Obfervation, that fome Difeafes grow
more violent, and others more remifs in courfe of Time:
So that the Remedies which might have avail'd for the an-
-tient B renning, may now fail as to the modern Pox.
The Procefs for the Cure, as deliver'd by _7. Arden, Chi-
rurgeon to K. Henry IV. is thus-Contra Incendium Prir-
gve ririlis interims ex calore F excoriatione flat talis fyrin-
ga (i. e. injeaio) lenitiva. Accipe lac Mulieris mafcalum
nutrientis F parum zacarium, Oleum Viole E Ptifan:
quibus commixtis per Syringam infundatur.
In an antient MS. written about the Year z300, is a
Receipt for B renning of. the ayntyl yat Men clepe the A-
pegalle; Galle being an old'Word for a running Sore. 'And
in another MS. written 5o Years after, is a Receipt for
Burning in that Part byte Woman. Simon Fijh, a zealous
Promoter of the Reformation, in his Supplication of .Bee-
gars, prefented to K. Heniy VIII. 1 530, fpeaking of the
Romigb Priefis, fays, T'eyl catch the Pocks of one Woman,
and bare 'em to another ;' they be burnt with one Woman,
and bare it to another: they catch the Lepry of one Wo-
man, and bare it to another.  And Boord, a Priefd and
Phyfician in the fame Reign, begins one of his Chapters
of his !'re'vay of Health, thus: l'he X 9th Chapter doth
Ae.7wo of the burning of an .Iarlotte. The'fame Author
adds, that if a Man be burnt with an Harlot, and do med-
dle with another Woman within a Day, he {hall burn the
Woman he 'Shall meddle withal: And as an immediate
Remedy againff the NBurning, he recommends the wafhing
the Padejda two or three times with Whitewine, or elfe
with Sack and, Water.- In another MS. of the Vocation
of ioh~n Ti'e to the Bilhoprick of Offory, written by him-
fel, he fpeaks of Dr. Hugh Weflon (who was Dean of
WF~indfor in I  6, but deprived by Cardinal Pole for Adul-
tery) thus * " At thisfDay is leacherdus Wef on, who is
more pra&'id in the Art of f reech-burning than all the
" Whores of the Stews.--e no: long ago brent a 4Beg-
"gar of St. Botolph's Par o.  'a See ST1ws. 2S
BURNING-GLASS, or 7iurning Mirror, a Machine,
whereby the Sun's Rays -re colleked into a Point and


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1B U R


by that means their Force and Ef&  extremely
fo as to burn Objeis placed therein. Burnin'
of two Kinds , the firI Convex, which tranfn
of Light, and in their Pafi'age refract or indir
wards its Axis; having the Property of Lens's,
according to the Laws of Reraffion: See LEN
PRACTION. The fecond, which is the more
K-    .                _123         .1


and in that Reflexion, incline them  to a Point in their
Axes; having the Properties of Mirrors, and ading accor-
ding to the Laws of Reflexion: which fee under MIRRoR
and REFLECTION.
The firfi, or Convex kind, Authors fuppofe to have been
unknown to the Antients; but the latter are generally al-
low'd. Hiftorians tell us, that Archimedes, by means
hereof, burnt a whole Fleet. Now tho the Efth related
be very improbable, yet does it fufficiently prove fuch
things were then known. The Machines here us'd, no
body doubts, were Metallick and Concave; and had their'
Focus by Reflexion: It being agreed, that the Antients
were unacquainted with the Refra&ed Foci of Convex
Glafes. Yet, M. de la Hire has difcover'd even thofe, in
the Clouds of fArifophanes; where Strepflades tells Socra-
tes, of an Expedient he had to pay his Debts, by means of
a round tranfparent Stone or Glafs, us'd in lighting of Fires -
by which he intended to melt the Obligation: which
in thofe Days was written on Wax. The Glafs here us'd
to light the Fire, and melt the Wax, M. de la Hire ob-
ferves, could not be Concave ; fince a reflected Focus com-
ing from below upwards, would have been exceedingly im-
proper for that Purpofe: And the old Scholiaft of Arijo-I
phanes, confirms the Sentiment. Pliny makes mention of
Globes of Glafs and Cryflal, which being expos'd to the
Sun, burnt the Clothes and Flelh on Peoples Backs; and
Ladfantius adds, that a glafs Sphere, full of Water, and
held in the Sun, lighted the Fire even in the coldeft Wea-
ther: which inconteflably proves the Effeas of Convex
Glafles. Indeed, there is fome Difficulty in conceiving
how they Thould know they burnt, without knowing they
magnify'd; which 'tis granted they did not, till towards
the Clofe of the XIIIth Century, when Spectacles and Te-
lefcopes were firfi thought on. For as to thofe Paiages in
Plautus which feem to intimate the Knowledge of Spec-
tacles, M. de la Hire obferves, they don't prove any fuch
thing : And he folves this, by obferving, that their 'Burn-
ing Glaffes being Spheres, either folid, or full of Water,
their Foci would be one fourth of their Diameter diflant
from 'em : If then their Diameter were fuppos'd half a
Foot, which is the moft we can allow, an Obje& mull be
at an Inch and a half's Diflance to perceive it magnify'd:
Thofe at greater Diflances do not appear greater, but only
more confus'd, thro the Glafs than out of it. 'Tis no won-
der, therefore, the magnifying Property of Convex Glafies
was unknown, and their burning one known: 'Tis more
wonderful there lhould be 300 Years between the Inventi-
on of Speaacles and Telefcopes.
Every Concave Mirror, or Speculum, collects the Rays
difpers'd thro its whole Concavity, after Reflexion, into a
Point or Focus, and is therefore a burning Mirror.
Hence, as the Focus is there where the Rays are the
mofi clofely contraced, if it be a Segment of a large
Sphere, its Breadth mufl not fubtend an Arch above j18
Degrees; if it be a Segment of a fmaller Sphere, its
Breadth may be 30 Degrees. Indeed, Kircher obferves,
that of all 'Burning Mirrors, thofe are the befi, whofe
Breadth does not fubtend an Arch of i8 Degrees, fo that
Experience and Demonfiration go toether.
As the Surface of a Mirror, Which is a Segment of a
larger, receives more Rays than another of a lefs, if the
Latitude of each fubtend an Arch of I8 Degrees; or even
n.^ or lers .rnrvit.^.A ;#F h.^ ^n.% .  LIS~A Ino   rats


-.- USIsv-,. .-I vaW ..  UC "%jal ; tUC n
greater Mirror will be greater than thofe of th,
And, as the Focus is contain'd between the
fifth Part of the Diameter, Mirrors that are,,
greater Spheres, bumr at ai greater Difiance
which are Segments of a fmaller.
Since, lafilly, the Burning depends on the I
Rays, and the Union of the Rays on the Coni
cal Figure; 'tis no wonder, that even wooden I
-or thofe prepared of Alabafler, Wo. cover'd
nay, even that thofe made of Paper, and c
Straw, Ihould be found to burn.
Among the Antients, the !Buring Miro
medes and Proculus are eminent ; by one ol
Roman . Ships befieging Syracfej, under the (
Marcellus. according to the Relations of zonal
Gaen, &c. and by the other, the Navy of AFi
ing 'Byzantium, according -to  A Zze~ies, were
mong theModerns, the ioli remarkable 'Burn
are thofe of Settal~, of Vette and Yf-chirobm
Canon of Padua mae awParaboical Mirror
3 i                       .  .


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