4 VQ geo 
Thefe genera! fafts are unfolded by an exceedingly cu¬ 
rious and interefting difplay of particulars. 
The eleventh tlfay is on the fubjedt of metall'c 
mines. It relates, that all the metals muft have exift- 
ed perfedl and uncontaminated in the chaotic flood. 
Gold is found naturally pure oftener than any of the 
other metals. Silver is much more frequently minera- 
lifed by fulphur, and alloyed with copper, antimony, 
lead, mercury, tin, or bifmuth. Nature prefents .ftill 
lefs of pure copper than of pure filver : the ores of cop¬ 
per are fcarcely ever free from fulphur. Of pure na¬ 
tive iron there are few or no fpecimens, except certain 
maifes found in Siberia and Peru, which feem to have 
bpen originally agglutinated by petrol, and left bare by 
tne diflblution of the mafles of other matters which 
once furrounded them. Native bifmuth accompanies 
the grey and the bright white ores of cobalt. Native 
arfenic is found only in the veins of primeval moun¬ 
tains : native mercury occurs in clay in mountains of fe- 
condary formation ; fulphurated ores have been formed 
at a time when fulphur, as well as metals, were in a 
date of extreme fubdivifion, in which they were much 
more foluble in fluids than they are at prefent. The 
cryftallifation of metallic ores was the confequence, in 
fonie inflances, of the diminution of the watery men- 
llruum, in others of flow precipitation. The veins of 
metals feem to have been, for the moft part, formed by 
depofition from water among the rifts and amid the llrata 
of the fofter rocks. It is in oxyds, in mineralifation by 
fulphur, in mixture with diflerent earths, and in amal¬ 
gamation with one another, that all the metals are the 
luofl: commonly found. 
The twelfth Elfay is profeflTedly to controvert what 
the late Dr. Hutton, of Edinburgh, had taught, that 
from eternity, this globe hud continued to pafs througli 
a feries ot revolutions, in which the land was ftill de- 
ftroyed. by external influences, and, in its ruins, propel¬ 
led into the ocean; while, on the other hand, internal 
fires were conftantly elevating new mountains under the 
ocean, and congionierating the materials driven into it; 
till, at Lift, the ocean changed its bed, that wliich had 
been dry land became fea, that which had been fea be¬ 
came dry land, and the deftrudlion of the new conti¬ 
nents, and the working of the volcanic fires under the 
new Teas, were again renewed. Mr. Kirwan attacks 
this theory as nnphilofophical.- Dr. Hutton defended 
his own lyftein. In this concluding elfay, however, 
Mr. Kirwan, in reply to Dr. Hutton’s defence, demon- 
ftrates, that igneous fufidn cannot have produced thofe 
phenomena which the doctor aferibes to it; affirms 
that volcanic fires are comparatively few and weak in 
their adfion ; and maintains, that the compolition of the 
fuperficial Itrata of our prelent continents, is fuch as 
could not poflibly be formed at the bottom of the fea.— 
See Dr. Hutton’s . theory refuted, under the article 
Earth, vol. vi. p. 177-201. 
Upon the'whole, it feems generally allowed that Mr. 
K irwati has exhibited a more confiftent fcheme of the 
fadts, and. analogies of geology, than any that has been 
before prefented to the world. If fubfequent geolo- 
gifts lhall continue to improve the fcience as Mr. Kir¬ 
wan has done, the world may, perhaps, at fome future 
period, form a corredt and faultlefs theory of the earth. 
GE'OMANGER,y. [^15 and A fortuneteller ; 
a cafter of figures, who pretends to foretel futurity by 
other means than the aftrologer.—Foruine-tellers, jug¬ 
glers, geoinancers, and the incantory impoftors, though 
commonly men of inferior rank, daily delude the vul¬ 
gar. Brown. 
GE'OMANCY,y. [yi) and ftavria ; gcomance, Fr.] The 
adt of calling figures; the aCt of foretelling by hgures 
w.hat ffiall happen.—According to fome there are four 
kinds ol divination; hydromaacy, pyromai.cy, acro- 
mancy, and geomancy, Ayliffe. 
GEO 
GEOMAN'TIC, adj. Pertaining to the adl of caft- 
ing figures : 
Two geom'antic figures were difplay’d 
Above his head, a warrior, and a maid; 
One when diredl, and one when retrograde. D'yden. 
GRO'METER, f. ^ysauErp-o^, Gr. geometre, Fr.] One 
Ikilled in geometry; a geometrician.—He became one 
of the chief gcomH rs of hio age. IVatts. 
GEO'ME iRAL, adj. \_gcometral, Fr. ] Pertaining to 
geometry. 
GEOME'TRIC, or Geometrical, (3(^'.[yia)|u.5Tpiicoi; 
geometrique, Fr, ; {rom geometry.] Pertaining to geome¬ 
try.—A geometrical fcheme is let in by the eyes, but the 
demonftration is difeerned by reafon. More. —Preferibed 
or laid down by geometry.—Muft men take the mea- 
fureof God juft by the {awlq geometrical proportions that 
he did, that gathered the heiglu and bignefs of Hercu¬ 
les by his foot ? S tillingJleet. 
Does not this wife philofopher aflert. 
That the vaft orb, which calls lb fair his beams. 
Is fuch, or not much bigger than he feems ? 
That the dimenfions of his glorious face 
Two geometric feet do fcarce furpals > Blackmore. 
Difpofed according to geometry.— Geometric }dii^er feem- 
eth. of affinity with the lafjis fanguinalit delcribed by Boe- 
tiiis ; but it is certainly one iort ofcrttci/omeV. Grew. 
Geometrical Curve, called alfo algebraical one, 
is that in which the relations between the abfcilfes and 
ordinates may be exprelled by a Unit; algebraical equa¬ 
tion. See Algebra. 
Geometrical Lines, as obfe^ved by Newton, arc 
diftingiiillied into clalfes, orders, or genera, according 
to the number of the dimenfions of the equation that ex. 
prelfestlie relation between the ordinates and abfcilfes; 
or, which amounts to the fame thing, according to tlte 
number of points in which they may be cut by a right 
line. 
Geometrical Locus, called alfo fimply Loan, or 
Place, is the path or track of fome certain geometrical 
determination, in which it always falls. 
Geometrical Meth on of the Ancients. The 
ancients eftabliffied the higher parts of their geometry 
on tlie fame principles as the elements of that fcience, 
by demonftrations of the fame kind ; aiitl they were 
careful nob to fuppole any thing done, till by a previous 
problem they had Ihewn that it could be done by abtu- 
ally performing it. Much lefs did they fiippofe any 
thing to be done that cannot be conceived; Inch as a 
line or feries to be aftually continued to infinity, or a 
magnitude diininillied till it become infinitely lefs than 
what it is. The elements into which they refolved 
magnitudes were finite, and fuch as might be conceived 
to be real. Unbounded feries have of late been intro¬ 
duced ; by which geometry, which ought to be perfeft- 
ly clear, is filled with myfteries. 
Geometrical Progression, aprogreffionin which 
the terms have all fucceffively the fame ratio : as i, 2, 
4, 8, 16, &c. where the common ratio is 2. The gene¬ 
ral and common property of a geometrical progreilion 
is, that the product of any two terms, or the fquare of 
any one lingle term, is equal to the produCt ot every 
ether two terms that are taken at an equal diftance on 
both fides from the former. 
Gikimetrical I’rofortion, called alfo fimply Pro¬ 
portion, is the fimilitude or equality of ratios, "i'hus, if 
a : b c : d, or a : b =.c : d, the terms a, b, c, d, are in 
geometrical proportion, alfo 6, 3, 14,7, are in geonnetri- 
cal proportion, becaule 6:3:: 14 : 7, or 6 ; 3 2= 14 : 7. 
GEOMET'RICALI.Y, adv. According to the laws 
of geometry.—’Tis poiFiblc geometrically to contrive fuch 
an artificial motion as lhall be ot greater,fwiftnefs than 
the revolutions of the heavens, Wilkins. —All the bones, 
muftles. 
