GEN 
That used in this country is mostly brought 
from Germany. The roots are the only 
part of the plant made use of in medicine. 
Gentian stands at the head of the stomachic 
bitters. 
GENTIANA, in botany, a genus of the 
Pentandria Digynia class and order. Natural 
order of Rotaceae. Gentian®, Jussieu. Es- 
sential character : corolla monopetalous ; 
capsule superior, two-valved, one-celled, 
with two longitudinal receptacles. There 
are fifty-three species. 
GENUS, among metaphysicians and lo- 
gicians, denotes a number of beings, which 
agree in certain general properties, com- 
mon to them all ; so that a genus is an ab- 
stract idea, expressed by some general 
name or term. 
A genus is an assemblage of several spe- 
cies ; that is, of several plants which re- 
semble one another in their most essential 
parts. Hence it is aptly enough compared 
to a family, all the relations of which bear 
the same surname, although every indivi- 
dual is distinguished by a particular spe- 
cific name. In botany the establishment 
of genera renders the subject more simple 
and easy, by abridging the number of 
names, and arranging under one denomina- 
tion, termed the generic name, several 
plants, which, though different in many 
other respects, are found invariably to 
possess certain relations in those essential 
parts, the flower and fruit. Plants of this 
kind are termed by botanists plant® conge- 
neres, that is, plants of the same genus. 
Linnaeus’s genera, contain a description 
of each particular part of fructification, its 
various relations, and different modes with 
respect to number, figure, situation, and 
proportion. Thus, all the different species 
of calyx, corolla, nectarium, stamina, See. 
furnish the observer with so many sensible, 
and essential characters. These characters 
the author denominates the letters or alpha- 
bet of botany. By studying, comparing, 
and, as it were, spelling these letters, the 
student in botany comes, at length, to read 
and understand the generical characters 
which the great. Creator has originally im- 
printed upon vegetables : for the genera 
and species, according to LiniKens, are 
solely the work of nature ; whilst the classes 
and orders are a combination of nature and 
art. Upon these principles, Linnaaus, in 
his genera plantarum, determines the gene- 
rical characters of all the plants there 
described. 
Genus, in natural history, a sub-division 
GEO 
of any class or order of natural beings, whe= 
ther of the animal, vegetable, or mineral 
kingdoms, all agreeing in certain common 
characters. 
GEOCENTRIC latitude of a planet, is 
its distance from the ecliptic as it is seen 
from the earth, which, even though the 
planet be in the same point of her orbit, is 
not constantly the same, but alters ac- 
cording to the position of the earth in 
respect to the planet. 
Geocentric place of a planet, the place 
wherein it appears to us from the earth, sup- 
posing the eye there fixed : or it is a point 
in the ecliptic to which a planet seen from 
the earth is referred. 
GEODiESIA, the same with surveying. 
See Surveying. 
GEOFFROYA, in botany, so named in 
honour Of Monsieur Geoffroy, a member of 
the academy at Paris, a genus of the Dia- 
delphia Decandria class and order. Natural 
order of Papilionacese or Leguminosse. Es- 
sential character : calyx five-cleft ; drupe 
ovate ; nut flatted. There are two species. 
GEOGRAPHY, is that science which 
exhibits the results of our investigations res- 
pecting the planet we inhabit, whether we 
consider its figure and the disposition of the. 
lands and water upon its surface, or the 
subdivisions which the different nations who 
inhabit it have made, by which it is con- 
sidered as forming kingdoms and states. 
The general curvature of the earth’s sur- 
face is easily observable in the disappear- 
ance of distant objects ; and, in particular, 
when the view is limited by the sea, the 
surface of which, from the common pro- 
perty of a fluid, becomes naturally smooth 
and horizontal; for it is well known that the 
sails and rigging of a ship come into view 
long before her hull, and that each part is 
the sooner seen as the eye is more elevated. 
On shore, the frequent inequalities of the 
solid parts of the earth usually cause the 
prospect to be bounded by some irregular 
prominence, as a hill, a tree, or a building, 
so that the general curvature is the less ob- 
servable. 
The surface of a lake, or sea, must be 
always perpendicular to the direction of a 
plumb line, which may be considered as the 
direction of the force of gravity ; and by 
means either of a plumb line, or of a spirit 
level, we may ascertain the angular situa- 
tion of any part of the earth’s surface with 
respect to a fixed star passing the meridian ; 
by going a little further north or south, and 
repeating the observation on the stat, we 
