H E D 
H E I 
902 
H e r 
HEDGE-Breakers, by 43 Eliz. e. 7. 
sliall pay such damages as a justice of the 
peace shall think lit ; and on nonpayment 
shall be whipped. And by 15 Car. II. c. 6. the 
constable may apprehend a person suspected, 
and by warrant of a justice, may search bn 
houses and other places; and if any hedge- 
wood shall be found, and he shall not give a 
good account how he came by the same, he 
shah be adjudged the stealer thereof. 
H EDGES. See EIusbandry. 
HEDVV1GEN, a genus of the octandria 
nacn >gynia class and order. The cal. is 
four-toothed ; the cor. four-cleft; style none; 
caps, tricoceous ; seed a nut. There is one 
species, a tree of St. Domingo. 
HEDYCARYA, a genus of the icosandria 
order, iu the dioecia class of plants. The ca- 
lyx of the male is cleft in eight or ten parts ; 
there is no corolla, nor are there any fila- 
ments; the antherae are in the bottom of the 
calyx, four-furrowed, and bearded at top. 
The calyx and corolla of the female are as in 
the male; the germs pedicellated; the nuts 
pedicellated and monospermous. There is 
one species, a tree of Guiana. 
I1EDYCREA, a genus of the class and 
order pentandria monogynia. The cal. is 
one-lcafed, hemispherical, five-toothed : cor. 
none : drupe oval, one-celled : nect. ovate, 
covered with fibres, one-celled ; shell hard. 
There is one species, a tree of Guiana. 
HEDY OSMUM, a genus of the class and 
order monoecia polyandria. The male is an 
ament with anthers; no cor. perianth, or 
filaments. The female has cal. three- 
toothed ; con none ; stvle one, three-cor- 
nered ; berry three-cornered, one-seeded. 
There are two species, shrubs of Jamaica. 
HJEDYOTIS, a genus of the monogynia 
order, in the tetrandria class of plants ; and 
in the natural method ranking under the 47th 
order, stellate, The corolla is monopeta- 
lous and funnel-shaped ; the capsule is bilo- 
cular, polyspermous, inferior. There are 
eight species, herbs of Ceylon, &c. 
HEDY PNOIS, a genus of the class and 
order syngenesia polygainia asqualis. r ]'he 
cal. is caiycled, with short scales ; seeds 
crowned with the calycle; recept. naked, 
hollow-dotted. ^ 
HEDYSARUM, a genus of the decan- 
dria order, in the diadelphia class of plants; 
and in the natural method ranking under the 
32d order, p ipilionacex. The carina of the 
corolla is transversely obtuse; the seed-ves- 
sel a legumen with monospermous joints. 
There are 90 species of this plant, of which 
the most remarkable are : 1 . The gyrans, or 
sensitive hedysarum, a native of the East In- 
dies, where it is called burrum cbundalli. It 
arrives at the height of four feet, and in au- 
tumn produces bunches of yellow flowers. 
The root is annual or biennial. It is atrisoli- 
011 s plant, and the lateral leaves are smaller 
than those at the end, and all day long they 
are in constant motion without any external 
impulse. They move up and down, and cir- 
cularly. This last motion is performed by 
the twisting of the footstalks; and while the 
one leaf is rising, its associate is generally 
descending. The motion downwards is 
quicker and morn irregular than the motion 
upwards, which is. steady and uniform. 'These 
motions are observable for the space of 24 
jiours in the leave* of a branch which is lop- 
ped off from the shrub, if it is kept in water. 
If from any obstacle the motion is retarded, 
upon the removal of that obstacle it is re- 
sumed with a greater degree of velocity. 2. 
The coronarium, or common biennial French 
honeysuckle, has large deeply-striking bien- 
nial roots; upright, hollow, smooth, very 
branchy stalks, three or four feet high, with 
pinnated leaves; and from between the leaves 
proceed long spikes of beautiful red flowers, 
succeeded by jointed seed-pods. The first 
species, being a native of hot climates, re- 
quires the common culture of tender exotics; 
the second is easily raised from seed in any of 
the common borders, and is very ornamental. 
HEEL. See Anatomy. 
Heel, in the sea-language. If a ship 
leans on one side, whether she is aground or 
afloat, then it is said she heels astai board, or 
aport; or that she heels offwards, or to the 
shore ; that is, inclines more to one side than 
to another. 
HEGIRA, in chronology, a celebrated 
epocha among the Mahometans. The event 
which gave rise to this epocha was the flight 
of Mahomet from Mecca, with his new prose- 
lytes, to avoid the persecution of the Korais- 
chites; who, being then most powerful in the 
city, could not bear that Mahomet should 
abolish idolatry, and establish his new reli- 
gion. This flight happened in the fourteenth 
year after Mahomet had commenced pro- 
phet: he retired to Medinq, which he made 
the place of his residence. 
H EIG HT, in geometry, is a perpendicular 
let fall from the vertex, or top, of any right- 
lined figure, upon the base or side subtending 
it. It is likewise the perpendicular height of 
any object above the horizon; and is found 
several ways: by two staffs, a plain mirror 
v. 1 1 the quadrant, theodolite, or some gradu- 
ated instrument, &c. 
The measuring of heights or distances is 
of two kinds: when the place or object is 
accessible, as when you can approach to its 
bottom ; or inaccessible, when it cannot be 
approached. 
Prob I. To measure an accessible height AB, by 
means of tnvo staffs. See plate Miscel. fig. 111. 
Let there be placed perpendicularly in the 
ground, a longer staff DE, likewise a shorter 
one FG, so that the observer may see A, the top 
of the height to be measured, over the ends D, 
F, of the two staffs; let FTI and DC, parallel 
to the horizon, meet DE and AB in LI and C ; 
then the triangles PHD, DCA, shall be equian- 
gular; for the angles at C and H are right ones : 
likewise the angle A is equal to FDH ; where- 
fore the remaining angles are also equal. There- 
fore, as FLI, the distance of the two staffs, is to 
HD, the excess of the longer staff above the 
shorter ; so is DC, the distance of the longer 
staff from the tower, to CA, the excess of the 
height of the tower above the longer staff; and 
thence CA will be found b}' the rule of three. 
To which if the length DE be added, you will 
have the whole height of the tower BA. 
Schol um. Another method may he occasionally 
contrived for measuring an accessible height ; as 
by the given length of the shadow' BD (fig. 112), 
I find out the height AB : for let there be erect- 
ed a staff CE, perpendicularly, producing the 
shadow EF ; then it will he as EF, the shadow 
of the staff, is to EC, the staff itself ; so is BD, 
the shadow of the tower, to BA, the height. 
Though the plane on which the shadow of rhe 
tower falls, he not parallel to the horizon, yet if 
the staff be erected in the same plane, the rule 
will be the same. 
Prob. IT. To measure an accessible height by means of 
a plain mirror. 
Let AB (fig. 113) be the height to be mea- 
sured ; let the mirror be placed at C, in the 
horizontal plane BD, at a known distance BC : 
let the observer go. back to D, till he see the 
image of the summit in the mirror, at a certain 
point of it, which he must diligently mark; and 
let DE be the height of the observer’s eve The 
triangles ABC and EDC, are equiangular; for 
the angles at D and B are right angles ; and 
ACB, ECD, are equal, being the angles of inci- 
dence and reflection of the ray AC ; wherefore 
the remaining angles at A and E, are also equal. 
Therefore it will be, as CD is to DE, so is CB 
to BA. 
The observer will be more exact, if, at the 
point D, a staff be placed in the ground per- 
pendicularly, over the top of which the observer 
may see a point of the glass exactly in a line be- 
twixt him and the tower. 
In place of a mirror may be used the surface 
of water, which naturally becomes parallel t* 
the horizon. 
Prob. III. To measure an accessible, height by the 
geomet ical quadrant , theodolite , tsf e. 
Let the angle C (fig. 114) be found. Then in 
the triangle ABC, right-angled at B (BC being 
supposed the horizontal distance of the observer 
from the tower), having the angle C, and the side 
BC, the required height will be found by the 
first case of plan trigonomety. Thus, suppose 
the angle C. 37° 24', and the horizontal distance, 
BC, 116, then the proportion will be as R * T 
Z.C ** CB * BA, the height. 
The tangent altitude 37° 24' - - 9.88341 
Log. CB 116 - - - 2.06446 
Added - 11. 9478 T 
Radius - 10.00000 
Height of the object AB 88.69 1,94787 
Supposing the observation made on the top of 
the tow r er, and the height of the tower to he 
known to find the distance of any object on the 
plane below ; it is only the converse of the 
former case. 
You may also, having the base and anHes, 
easily find the hypothenuse AC, or how far it 
is from the top of the tower to the station, by 
the second case of right-angled triangles : and 
it is useful in many cases. 
PltOB. IV. To measure an inaccessible height by the 
geometrical quadrant , CA. at tnvo stations. 
Let the angle ACB be observed (fig, 115); let 
the observer go from C, to the second station D, 
in the right line BCD; and after measuring this 
distance CD, take the angle ADC likewise with 
the quadrant. Then in the triangle ACD, which 
is formed by the two visual rays AD, AC, and 
the distance of the two stations D and C, there 
is given the angle ADC, with the angle ACD, 
because the angle ACB was given before; there- 
fore the remaining angle CAD is given likewise. 
But the distance of the stations C and D is also 
given ; therefore by the second case of oblique- 
angled trigonometry, the side AC will be found. 
Wherefore, in the right-angled triangle ABC, 
all the angles and the hypothenuse AC are given ; 
consequently by the third case of plain trigo- 
nometry, the height sought, AB, may be found; 
as also the distance of the station C, from AB, 
the perpendicular within the hill or inaccessible 
height. 
Example. Suppose the angle at C 43° 30', and 
the angle at D 32 ’ 12', and the distance CD, be- 
twixt the two stations, 112 feet ; then die angle 
DAC will be. IP 1 IS , and the angle CAB 46° 30 7 . 
Hence for CA, the proportion will be as S / 
DAC ; DC ; : S. Z. D ; CA. 
