553 REF 
pn ration or clarification of liquors. Gold and 
silver may be refined by several methods, 
whicn are all founded on die essential pro- 
pel ties oi these metals, and acquire different 
names according to their kinds. Tims, for 
instance, gold having the property which no 
omer metai, not even silver, has, of resisting 
tue actum or s .lplmr, ol antimony, of nitrous 
acal , dl marine acid, may be purified by these 
a units irom all other metallic substances, and 
< ojiiequently may be reiinetl. These ope- 
i a too ns are distinguished by proper names, as 
purification of gold by antimony, parting, 
concentrated parting, dry parting. In a 
similar manner, as silver has the property, 
wiiicii t he imperfect metals have not, of re- 
sisting the action ot nitre, it may be refined 
by this salt; but the term refining is chicJly 
applied to the purification of gold and silver 
by lea 1 in the cupel. This is performed by 
the destruction, vitrification, and scorification, 
of ail the extraneous and destructible metallic 
substances with which they are allayed. 
As none but the perfect metals can resist 
the combined action of air and fire, without 
losing their inflammable principle and being 
changed into earthy or vitreous matters, in- 
capable ot remaining any longer united with 
substances in a metallic state, there is then a 
possibility ot purifying gold and silver from 
all al!ay r of imperfect metals merely by' the I 
action of tire and air, only by keeping them 
fused till all the allay is destroyed ; but this 
purification would be very expensive, from 
the great consumption of fuel, and would be 
exceedingly tedious. Silver allayed with cop- 
per has been exposed longer than 60 hours to 
a glass-house fire without being perfectly re- 
fined; the reason of which is,' that when a 
small quantity only of imperfect metal re- 
mains united with gold or silver, it is covered 
and protected from the action of the air, 
which is necessary for the combustion of the 
imperfect metals, as of all combustible mat- 
ters. 
This refining of gold and silver merely by 
the action of lire, which was the only method 
antieiitlv known, was very long, difficult, ex- 
pensive, and imperfect but a much shorter 
and more advantageous method has been dis- 
covered. This method consists in adding to 
the allayed gold and silver a certain quantity 
of lead, and exposing afterwards this mixture 
to the action of the fire. Lead is one of the 
metals which loses most quickly and easily a 
sufficient quantity of Us inflammable prin- 
ciple to cease to be in a metallic state ; but, 
at the same time, this metal has the remark- 
able property of retaining, notwithstanding 
the action of the fire, enough of this same 
inflammable princ'ple to be very easily melt- 
ed into a vitrified and powerfully vilrifving 
matter, called litharge. 
The lead then which is to be added to the 
gold and silver to be refin'd, or which hap- 
pens naturally to be mixed with these metals, 
produces in their refining the following ad- 
vantages : 1. By increasing the proportion 
of imperfect metals, it prevents them from 
being so well covered and protecte 1 by the 
perfect metals. 2. By uniting wit i these im- 
perfect metals, it communicates to them a 
property it has of losing very easily a great 
part of its inflammable principle. 3. By its 
vitrifying and fusing property which it exer- 
cises with all its force upon the calcined and 
naturally refractory parts of the other metals. 
II J5 f 
it facilitates and accelerates the fusion, the 
scorification, and the separation, of these 
metals. r l liese are the advantages procured 
by lead in the refining of gold and silver. 
The lead, which in this operation is scorifi- 
ed, and scorifies along with it the- imperfect 
metals, separates from the metallic mass, 
with which it is then incapable of remaining 
united. It lloats upon the surface of the 
melted mass, because, by losing part of its 
phlogiston, it loses also part of its specific 
gravity, and lastly it vitrifies. 
These vitrified and melted matters accu- 
mulating more and more upon the surface of 
the metal while the operation advances, would 
protect this surface from the contact of air 
which is so absolutely necessary for the scori- 
fication of the rest, and would thus stop the 
progress of the operation, which could never 
be finished if a method had not been con- 
trived for their removal. T his removal of 
the vitrified matter is procured either by the 
nature of the vessel in which the melted 
matter is contained, and which being porous, 
absorbs and imbibes the scorified matter as 
fast as it is formed-; or by a channel cut in the 
edge of the vessel, through which the matter 
flows out. 
1 lie vessel in which the refining is per- 
formed is flat and shallow, that the matter 
which it contains may present to the air the 
greatest surface possible. "This form resem- 
bles that of a cup, and hence it has been 
called cupel. The furnace ought to be 
vaulted, that the heat may be applied upon 
the surface of the metal during the whole 
time of the operation. Upon this surface a 
crust of dark-coloured pellicle is continually 
forming. In the instant when all the im- 
perfect metal is destroyed, and consequently 
the scorification ceases, the surface of the 
perfect metals is seen, and appears clean and 
brilliant. This forms a kind of fulguration 
or coruscation : by this mark the metal is 
known to be refined. It the operation is so 
conducted that the metal sustains only the 
precise degree of heat necessary to keep it 
fused before it is perfectly refined, we may 
observe that it fixes or becomes solid all at 
once in the very instant of the coruscation; 
because a greater heat is required to keep 
silver or gold in fusion when they are pure 
than when allayed with lead. 
1 he operation of refining maybe performed 
in small or in large quantities upon the same 
principles, but only with some differences in 
(he management. As the refining of small 
quantities of perfect metals is performed in 
the same manner as these metals are assayed, 
the assay being only a very accurate refining’ 
we refer to the article Assaying. 
R EL LECTION of the rays of light , in 
catoptrics, is their return, after approaching 
so near the surfaces of bodies, as to be re- 
pelled, or driven backwards. See Optics. 
^ Reflector, a mirror or looking-glass. 
Lor the laws of reflexion see Optics; and for 
the method of silvering or foliating glass to 
make it reflect, see Foliating of looking- 
glasses. Vol. I. p. 758. 
REFRACTION of the rays of light. See 
Optics. 
Refraction, in astronomy, is an inflection 
of tiie rays of light proceeding from the hea- 
venly bodies, in passing through the atino- 
R E G 
sphere, by which their apparent altitudes are 
increased. See Astronomy, Vol. R pa^e 
171. r u 
Refraction in island crystal. There is 
a double refraction in this substance, con- 
trary ways, by which not only oblique rays 
are divided into two, and retracted into op- 
posite parts, but even perpendicular rays 
are one-half refracted. 
RbT TANGIBILITY of light, the dis- 
position of rays to be refracted. See Optics. 
REGALIA, in law, the rights and pre- 
rogatives, of a king; which, according to ci- 
vilians, are six, viz.l, the power of judicature; 
2, the power of life and death ; 3, the power 
ot peace and war ; 4, a right to such goods 
as have no owner, as waifs, estrays^ &c. 
5, assessments ; and, 6, the coinage ‘of mo- 
ney. 
Regalia is also used for the apparatus of a 
coronation, as the crown, the sceptre with the 
cross, that with tiie clove, St. Edward’s staff, 
tiie globe, and the orb with the cross, four 
several swords, Ac. 
REGARDANT, in heraldry, signifies 
looking behind ; and is used for a lion, or 
other beast, with his face turned towards his 
tail. See Heraldry. 
] REGENT , one who governs a kingdom 
during tiie minority or absence of tiie king. 
In France, the queen-mother has tiie regency 
of tiie kingdom during tiie minority of the 
king, under tiie title of queen-regent.’ 
Regent also signifies a professor of arts 
and sciences in a college, who has a set of 
pupils under his care; but here regent is 
generally restrained to tiie lower classes, as 
regent of rhetoric, regent of logic, & c. those 
of philosophy are rather called professors. The 
foreign universities are generally composed of 
doctors, professors, and regents. 
REGIMEN, the regulation of diet, and • 
in a more general sense, of all the non-na- 
turals, with a view to preserve or restore 
health. See Materia Medica, article 
Dietetics. 
Regimen, in grammar, that part of 
syntax or construction which regulates the 
dependancy of words, and the alterations 
which one occasions in another. 
REGIMENT, a term applied to any body 
of troops ; which, it cavalry, consists of one 
or more squadrons, commanded by a colonel ; 
and, it infantry, of one or more battalions, 
eac h commanded in the same manner. The 
squadrons in cavalry regiments are divided, 
sometimes into six, and sometimes into nine 
troops. The battalions of British infantry 
are generally divided into ten companies, two 
of which are called the flanks; one on the 
right consisting of grenadiers, and another oil 
the left formed of light troops. There is not, 
however, any established rule on this head ; 
as both cavalry and infantry regiments differ 
according to the exigencies of service in time 
of war, or the principles of economy in time 
of peace. Me are humbly ot cpinon, that 
every regiment of foot should consist of 2400 
men, making three battalions of 800 each. 
The German regiments frequently consist of 
2000 men ; and the regiment ot Picardy in 
the old French service had 6000. The French 
have made a distinction between the com- 
manding officer of a regiment of cavalry, and 
the commanding officer of a regiment of in- 
fantry : the former was stiled mestre de 
camp; the latter colonel, as with as. 
