F R I 
and confiderable. Mr. Hawkftee gives a number of ex¬ 
periments of this kind ; particularly of the attrition or 
fridiion of glafs, under various circumftances; the refult 
of which was, that it yielded light, and became eleffrical. 
Indeed all bodies by friftion are brought to conceive heat; 
many of them to emit light; particularly a cal’s back, 
fugar, beaten fulphur, mercury, fea water, gold, copper, 
&c. but above all, diamonds, which when brilkly rubbed 
againft glafs, gold, or the like, yield a light equal to that 
of a live coal when blown by the bellows. 
Friction, in mechanics, denotes the refiftance a mov¬ 
ing body meets with from the furface on which it moves. 
IViftion arifes from the roiighnefs or afperity of the 
furface of the body moved on, and that of the body 
moving; for fuch furfaces confiding alternately of emi- 
nences and cavities, either the eminences of the one muft 
be raifed over thofe of the other, or they muft be both 
broken and worn off: but neither can happen without 
motion, nor can motion be produced without a force im- 
prefted. Hence the force applied to move the body is 
either wholly or partly fpent on this eftedl ; and confe- 
quently there arifes a refiftance, or friftion, which will 
be greater as the eminences are greater, and the fubftance 
the harder; and as the body, by continual friiSion, be¬ 
comes more and more polifhed, the fri6lion diminiflies. 
As the friflion is lefs in any body that rolls, than when 
it Aides, hence in machines, left the friftion Ihould em¬ 
ploy a great part of the power, care is to be taken that 
no part of the machine Aide along another, if it can be 
avoided ; but rather that they roll, or turn upon each 
other. With this view it may be proper to lay the axes 
of cylinders, not in a groove or concave matrix, as ufual, 
but between little wheels, called friftion wheels, move- 
able on their refpeftive axes; for by this contrivance, 
the friftion is transferred from the circumference of thofe 
wheels to their pivots. And in like manner the frittion 
may be ftill farther diminiftied, by making the axis 
of thofe wheels reft upon other friftion wheels that 
turn round with them. This was long fince recommended 
by P. Cafabus; and experience confirms the truth of it. 
Hence alfo it is, that a pulley moveable on its axis refifts 
lefs than if it were fixed, and the cord Aiding over the 
circumference. And the fame may be obferved of the 
wheels of coaches, and other carriages. Indeed about 
twenty years ago, friction balls or rollers were placed 
within the naves of carriage wheels by forne perfons, par¬ 
ticularly a Mr. Varlo ; and lately Mr. Garnett had a pa¬ 
tent for an improved manner of applying friftion wlieels 
to any axis, as of carriages, blocks or pulleys, fcale 
beams, &c. in which the inclofed wheels or rollers are 
kept always at the fame diftance by connefting rods or 
bars. From thefe principles, with the affiftance of the 
higher geometry, Olaus Roemer determined the figure of 
the teeth of wheels that fliould make the leaft refiftance 
poflible, which he found fhould be epycloids. And the 
fame was afterwards demonftrated by De la Hire, and 
Camus.—-See the article Mechanics. 
Friction, in a medical fenfe, if duly repeated, will do 
more in the recovery-of health, and towards the fupport 
of it, than is generally apprehended; it promotes per- 
fpiration, quickens the circulation, and opens the finer 
veftels through which thofe difcharges are made, on 
which health and vigour much depend. Friftion con¬ 
tributes not only to the conveyance of medicine into the 
body, but alfo to their adlion and ufefulnefs when intro¬ 
duced. This means of health is beft ufed when the 
prima via are moft empty, when the chylopoetic organs 
are too languid. Friftions with rough cloths over the 
whole belly, when the patient is fading, produces advan¬ 
tageous efiefts. Gentle friftion with pinguious fubftances 
relax; but ftrongfriffion with rough dry cloths ftrengthen. 
It has been coniidered particularly iileful in cafes of af- 
cites, and many others, where the adtion of the abforbent 
fyftem is neceflary to be promoted. 
FRlDAW'j a town of Ggrraanyj in the duchy of Sti- 
F R I 43 
ria: nine mi\es eaft-foutli-eaft of Pettaw, and 104 foiuh 
of Vienna. Lat. 46. 30. N. Ion. 33. 57. E. Ferro. 
FRl'DAY, f. [ppije Sax.] The fixth day of 
the week, fo called from Friga, or Friya, a goddefs wor- 
ftiipped by the Saxons on this day. It is a faft-day, in 
memory of our Saviour’s crucifixion, unlefs Chriftmas- 
day happen to fall on Friday, when it is the greateft fef- 
tival in the year.—Goos? Friday is that next before Eafter, 
on which day our Saviour was crucified.—Among aftro- 
logers, Friday has been generally confidered as the mod 
changeable and unfettled day in the week ; whence the 
poet, in a peevifti humour, caft the metaphor at the ladies 1 
For Venus, like her day, will change her cheer. 
And feldom ftiall we fee a Friday clear. Dryden. 
FRID'BERG, a town of Germany, in the duchy of 
Stiria : thirty-two miles eaft of Pruck, and forty-two 
fouth of Vienna; Lat. 47. 32. N. Ion. 33. 58. E. Ferro. 
FRID'BERG, or Friedberg, a town of Germany, in 
the circle of Upper Bavaria. This town was facked by 
the Swedes in 1632, and taken by the Auftrians in 1743: 
four miles foutlueaft of Augfburg, and twenty-eight weft- 
north-weft of Munich. Lat. 48. 20. N. Ion. 28. 37. E, 
Ferro. 
FRID'BERG, or Friedberg, an imperial town of 
Germany, in the circle of the Upper Rhine, on the Eftoach, 
in the Witteravia, which holds the twelfth feat on tlie 
bench of the imperial towns of the Rhine, and fits and 
votes at the diets of the Upper Rhine. In the matricula 
of the empire it is charged twenty-four florins, and to 
the chamber of Wetzlar twenty-nine rix-dollars twenty- 
nine kruitzers : twelve miles north of Frankfort on the 
Maine, and twenty.eight eaft-north-eaft of Mentz. Lat. 
50. 14. N. Ion. 26. 23. E. Ferro. 
FRI'DECK, a town of Pruftia, in the territory of 
Culm; twelve miles eaft of Culm. 
FRI'DECK, a town of Silefia, in the principality of 
Tefchen: ten miles Weft-fouth-weft of Tefchen, and tern 
fouth of Oderberg. 
FRI'DEGAST, an idol worfliipped by the ancient 
Britons. 
FRID'ERICHSBERG, a fort and colony on the coafl: 
of Guinea : about twenty-five leagues from Cape Coalk 
Caftle. 
FRID'RRICHSHALL. See Fredericshall. 
FRI D'KRICH’s-ODE, a town of Denmark, in'Jut¬ 
land, built by Frederic HI. near the fea. It was taken- 
by the Swedes, in 1657 : fifty miles north of Slefwick. 
FR I'DEWALDE, a town of Germany, in the circle of 
Weftphalia, and county of Sayn; endowed, in 1324, with 
the fame privileges as Frankfort, but not to fo much ad-- 
vantage : it is a fief of Heffe Darmftadt : nine miles fouth 
of Siegen. 
FRI'DEWALDE, a town of Germany, in the circle 
of the Upper Rhine, and principality of Hefte Caffe! : 
eighteen miles weft of Eifenach, and thirty-five fouth- 
fouth-eaft of Cafiel. 
FRI'DING, a town of Germany, in the A-uftrian Swa¬ 
bia, on the Danube : twenty miles fouth-eaftof Tubingen, 
FRID'LAND, a town of Pruftia, in the province of 
Natangen : twenty miles fouth-eaft of Konigfberg. 
FRID'MAN, a town of Hungary: feventeen miles- 
north-nortli-weft of Palotza.. 
FRl'DO, a town of Italy, in the kingdom of Naples,, 
and province of Bafilicata : fevea milcs-eafl-foulh-eaft of 
Potenza. 
FRID'RICFISTEIN, a town of Germany, in the ducliy- 
of Carniola:;; one mile north-weft of Gottfcliee. 
FRID'STOLL, yi [Sax. ppib, pax, and j’Tol, yJafM.] 
A feat, chair, or place of peace, where, in ancient times, 
criminals flew for fafety and protection. In the charter 
of immunities granted to the church of St. Peter in 
York by Henry 1 . and confirmed anno 5 Hen. VII. fridftol! 
is expounded cathedra pads & quietudinis, &c. And there 
were, many fuch in England 5 but the moft famous-was 
afr 
