EXT 
EXT 
ties, are exterminated by the rules for re- 
ducing equations. See Algebra. 
EX TI NGUIS H M ENT, in law: wherever 
•a right, title, or interest is destroyed, or 
taken away by the act of God, operation of 
law, or act of the party, this is called an ex- 
tinguishment. 
Of the extinguishment of rents. — If a lessor 
purchases the tenantcy from his lessee, lie 
cannot have both the rent and the land ; nor 
I can the tenant be under any obligation to pay 
the rent when the land, which was the consi- 
deration thereof, is returned by the lessor into 
1 his own hands ; and this resumption or pur- 
chase of the tenantcy makes what is properly 
called an extinguishment of the rent. 
As to the extinguishment of copyholds, it 
is laid down as a general rule, that any act of 
the copyholder, which denotes his intention 
to hold no longer of his lord, amounting to a 
determination of hi,s will, is an extinguish- 
ment of his copyhold. Hutt. 81. 
! Of the extinguishment of common. — If a 
commoner release his common in one acre, 
it is an extinguishment of the whole com- 
mon. Show. 350. 
Of the extinguishment of debts. — A cre- 
ditor’s accepting a higher security than lie 
had before is an extinguishment of the first 
debt ; as if a creditor by simple contract ac- 
cepts an obligation, this extinguishes the sim- 
ple-contract debt. 1 Rol. Abr. 470 and 471. 
Extinguishment of services. The 
lord purchases or accepts parcel of the te- 
nantcy, out of which an entire service is to be 
paid or done; by this the whole service will 
be extinct : but if the service is pro bono 
publico, then no part of it shall be extin- 
guished : and homage and fealty are not 
subject to extinguishment by the lord’s pur- 
chasing part of the land. 6 Rep. 105. 
Extinguishment of ways. If a man 
has a highway as appendant, and after 
purchases the land wherein this wav is, the 
way is extinct : though a way of necessity, 
to market, or to church, or to arable land, 
See. is not extinguished by purchase of 
grounds, or unity of possession, 1 Inst. 155. 
EXTORTION, signifies any oppression 
by colour or pretence of right ; and in this 
respect it is said to be more heinous than 
robbery itself, as also that it is usually attend- 
ed with the aggravating sin of perjury. Co. 
Lit. 368. 
At common law extortion is severely pu- 
nishable at the king’s suit by fine and im- 
prisonment, and by a removal from the of- 
fice in the execution whereof it was com- 
mitted. 31 Eliz. c. 5. And this statute adds 
a greater penalty than the common law gave ; 
for hereby the plaintiff shall recover his dou- 
ble damages. 2 Inst. 210. See Colour of 
Office. 
EXTRACT, in pharmacy, is a solution 
of the purer parts of a mixed body inspis- 
sated, by distillation or evaporation, nearly to 
the consistence of honey. See Pharmacy. 
EXTRACTION, in surgery, is the draw- 
ing any foreign matter out of the body by 
the hand, or by the help of instruments. ' See 
Surgery. 
Extraction of roots, in algebra and 
arithmetic, the method of finding the root of 
any power or number. See Algebra, and 
Arithmetic. 
EXTRACTOR, in midwifery, an instru- 
Vol. I. 
< 
ment, or forceps, for extracting children by 
the head. See Midwifery. 
EXTRA-JUDICIAL, is when judgment 
is given in a cause or case not depending in 
that court where such judgment is given, or 
wherein the judge has no jurisdiction. 
EXTRA-PAROCHIAL, out of any pa- 
rish ; privileged or exempted from the duties 
of a parish. If a place is extra-parochial, and 
has not the face of a parish, the justices have 
no authority to send any poor person thither: 
possibly a place extra-parochial may be tax- 
ed in aid of a parish, but a parish shall not in 
aid of that. 2 Salk. 486. 
EXTRAVAGANTES, those decretal 
epistles which were published after the Cle- 
mentines. They were so called because, at 
first, they were not digested or ranged with 
the other papal constitutions, but seemed to 
be detached from the canon law. They con- 
tinued to be called by the same name when 
they were afterwards inserted in the body of 
the canon law. The first extravagantes are 
those of John XXII. successor of Clement V. : 
the last collection was brought down to the 
year 1483, and was called the common extra- 
vagantes, notwithstanding that they were 
likewise incorporated with the rest of the 
canon law. 
EXTRAVASATION, in contusions, fis- 
sures, depressions, fractures, and other acci- 
dents of the cranium, is when one or more 
of the blood-vessels that are distributed on the 
dura mater, are broken or divided, whereby 
there is such a discharge of blood as greatly 
oppresses the brain, and disturbs its offices ; 
frequently bringing on violent pains and other 
mischiefs, and at length death itself, unless the 
patient is timely relieved. See Surgery. 
EXTREMES, in logic, the terms express- 
ing the two ideas whose relation we enquire 
after in a syllogism. 
Extreme and mean proportion, in geo- 
metry, is when a line AB (Plate Miscell. fig. 
88) is so divided in F, that the rectangle 
under the whole line AB, and the lesser seg- 
ment FB, is equal to the square of the greater 
segment AF. 
Let a square be formed upon the line AB, 
and one of its sides AC be equally divided in 
the point D ; draw DB, and take the line 
DG equal to the line BD ; then the square 
AGUE will be equal to the rectangle FE. 
For since the line AC is equally divided in 
the point D, and is lengthened by the line 
AG, the rectangle CH, together with the 
square of the line AD, will (by 6.2. El.) 
be equal to the square of the line DG or 
DB. But the square AE, with the square of 
the line AD, is also equal (47.1.) to the 
square of the line DB. Therefore the square 
AE is equal to the rectangle CII. Taking 
then away from both the rectangle CF, the 
rectangle FE will be equal to the square FG. 
But no number can be so divided into two 
parts, as is demonstrated by Clavius, in his 
commentaries upon lib. 9. of Euclid ; w hich 
is evident enough thus : Let a be the num- 
ber, and x the greater part ; then the lesser 
part will be « — x, and so aa — ax xx, and 
thence .*■ = ; and since the squar e 
root of 5 cannot be had in numbers exactly, 
it is plain that the value of x partly consist- 
ing of the square root, multiplied by a, can- 
not be had exactly in numbers neither. 
4S « 
EVE 68£) 
Extremes, conjunct and disjunct. See 
Trigonometry, spherical. 
EXUVLE, among 'naturalists, denote the 
cast-off parts or coverings of animals, as the 
skins of serpents, caterpillars, and other in- 
sects. See Eruca. 
EYE, in anatomy, the organ of sight, or 
that part of the body whereby visible objects 
are represented to the mind. See Anatomy, 
Optics, and Physiology. 
Motions of the eye are either external or 
internal. The external motion is that per- 
formed by its four straight and two oblique 
muscles, whereby the whole globe of the eye 
changes its situation or direction. The sphe- 
rical figure of our eyes, and their loose con- 
nection to the edge of the orbit by the tunica 
conjunctiva, which is soft, flexible, and yield- 
ing, does excellently dispose them to be 
moved this or the other way, according to 
the situation of the object we would view'. 
By the membranes the eye is connected 
to the edge of the orbit, which being soft 
and flexible, they do in such a manner 
as not in the least to impede its necessary 
motions; and that great quantity of fat placed 
all round the globe, betwixt it and the orbit, 
lubricates and softens the eye, and renders 
its motions more easy : hence arise the three 
following remarkable observations : 
I. When nature has denied the head any 
motion, it is observable that she has, with 
great care and industry, provided for this de- 
fect. To this purpose belongs the surprising 
beautiful and curious mechanism observable 
in the immoveable eyes of flies, wasps, &c. 
They nearly resemble two protuberant he- 
mispheres, each consisting of a prodigious 
number of other little segments of a sphere, 
all which segments are perforated by a hole, 
which may be called their pupil, in which 
this is remarkable ; that every foramen, or 
pupil, is of a lenticular nature, so that we 
see objects through them topsy-turvy, as 
through so many convex glasses : they even 
become a small telescope, when there is a due 
focal distance between them, and the lens of 
the microscope by which they are viewed. 
Leuwenhoek’s observations make it probable 
that every lens of the cornea supplies the 
place of the crystalline humour, which seems 
to be wanting in those creatures ; and that 
each has a distinct branch of the optic nerve 
answering to it, upon which the images ate 
painted : so that as most animals are binocu- 
lar, and spiders for the most part octonocu- 
lar, so flies, &c. are multocular, having in 
effect as many eyes as there are perforations 
in the cornea, by which means (as other crea- 
tures with but two eyes are obliged, by the 
contraction of the muscles above-enumerat- 
ed, to turn their eyes to objects) these have 
some or other of their pupils always ready 
placed towards objects nearly all Ground 
them : whence they are so far from being de- 
nied any benefit of this noble and most neces- 
sary sense of sight, that they have probably 
more of it than other creatures, answering to 
their necessities and ways of living. 
II. As in man and most other creatures, 
the eyes are situated in the head, because, 
among other reasons, it is the most conve- 
nient place for their defence and security, be- 
ing composed of hard bones, wherpin are 
formed two large strong sinuses, or sockets, 
commonly called orbits, for the convenient 
lodging of these tender organs, and securing 
