PER 
580 PER 
circumftances, by eafing thofe that were overcharged, and 
raifing the taxation if too low. 
PERiE'THUS, in ancient geography, a town of the 
Peloponnefus, in Arcadia. Paufanias fays, that among 
the ruins of this town there was vifible a temple of the 
god Pan. 
PERAFI'TA, a town of Spain, in Catalonia: ten 
miles north-north-weft of Vique. 
To PER'AGRATE, v. n. [from the Lat. per, through, 
and ager, a field.] To wander through the country; to 
rove about. 
PER AGRA'TION, f. The aft of palling through any 
ftate or fpace.—A month of peragration is the time of 
the moon’s revolution from any part of the zodiac unto 
the fame again, and this containeth but twenty-feven 
days and eight hours. Brown. 
PERAGU', /. in botany. See Clerodendrum. 
PERAGU'A. See Cassine. 
PERALA'DA, a town of Spain, in Catalonia: twenty- 
two miles north-north-eaft of Gerona. 
PERA'LES, a town of Portugal, on the left bank of 
the Tagus, oppofite Abrantes. 
PERAL'TA, a town of Spain, in Navarre, celebrated 
for its wine s feven miles fouth-fouth-weft of Olite. 
PERAL'TA (Francifco de), a Jefuit, and Moderator 
of the Englilli college at Seville. He is to be enumerated 
among the foreigners who have written upon Englilli 
liiftory, having publilhed “ An Account of the State of 
the Catholick Religion in England, the Perfecution of 
the Catholicks, and the Martyrdom of two Priefts and 
one Layman in that Country,” Seville, 1616. He alfo 
edits “ A Letter from P. Rodrigo de Cabredo, giving an 
Account of the happy Death of the Lady Donna Louifa 
de Carvajal in London,” Seville, 1614. Gen. Biog. 
PERALU', f. in botany. See Ficus. 
PERAM', a fmall ifland in the Gulf of Cambay. Lat. 
si. 30. N. Ion. 72. 3. E. 
PERA'MA, f. in botany. See Mattuschkjea. 
To PER AM'BULATE, v. a. [from the Lat. per, 
through, and ambulo, to walk.] To walk through. To 
furvey, by palling through.—Perfons'the lord deputy 
fliould nominate to view and perambulate Irilh territories, 
and thereupon to divide and limit the fame. Davies on 
Ireland. —To vilit the boundaries of the parifh. 
PERAMBULA'TION, f The aft of palling through 
or wandering over.—The duke looked ftillforthe coming 
backof the Armada, even when they were wandering and 
making their perambulation of the northern feas. Bacon. 
—A travelling furvey.—France is a fquare five hundred 
and fifty miles traverfe, thronging with fuch multitudes, 
that the general calcul, made in the laft perambulation, 
exceed eighteen millions. Howell. —A diftrift; limit of 
jurifdiftion.—It might in point of confcience be demand¬ 
ed, by what authority a private perfon can extend a per- 
fonal correftion beyond the perfons and bounds of his 
own perambulation? Holyday. —Survey of the bounds of 
the parifh annually performed.— Per ambulation of parifhes 
is to be made by the minifter, churchwardens, and pa- 
rifhioners, by going round the fame once a-year, in or 
about Afcenlion week : and the parifhioners may well 
juftify going over any man’s land in their perambulation, 
according to ufage ; and it is faid may abate all nuifances 
in their way. Jacob. 
PERAM'BULATOR, /". A wheel for meafuring roads. 
—The method of doing this is either with an inftrument 
and chain, or elfe with a perambulator, or meafuring- 
wheel. Alingham on Maps. 
Perambulator is alfo an inftrument for meafuring dif- 
tances ; called alfo odometer, pedometer, way-wifer, and 
Jurveying-wheel. 
This ufeful and common inftrument is reprefented on 
the fame Plate with the Pentagraph, at p. 567. This 
perambulator confifts of a wheel A, fig. 3, two feet feven 
inches and a half in diameter; confequently half a pole, 
or eight feet three inches, in circumference. On one end 
of the axis (drawn- feparately at fig. 4,) is a nut, three 
quarters of an inch in diameter, and divided into eight 
teeth ; which, upon moving the wheel round, fall into 
the eight teeth of another nut c, fixed on one end of an 
iron-rod Q, and thus turn the rod once round in the 
time the wheel makes one revolution. This rod, lying 
along a groove in the fide of the carriage of the inftru¬ 
ment, has at its other end a fquare hole, into which is 
fitted the end b of a fmall cylinder P. This cylinder is 
difpofed under the dial-plate of a movement, at the end 
of the carriage B, in fuch a manner as to be moveable 
about its axis : its end a (fig. 5.) is cut into a perpetual 
ferew, which falling into the 32 teeth of awheel perpen¬ 
dicular thereto, upon driving the inftrument forward, 
that wheel makes a revolution each 16th pole. On the 
axis of this wheel is a pinion with fix teeth, which fal¬ 
ling into the teeth of another wheel of 60 teeth, carries 
it round every 160th pole, or half a mile. This laft 
wheel, carrying a hand or index round with it over the 
divifions of a dial-plate, whofe outer limb is divided into 
160 parts, correfponding to the 160 poles, points out the 
number of poles paifed over. Again, on the axis of this 
laft wheel is a pinion, containing 20 teeth, which falling 
into the teeth of a third wheel which hath 40 teeth, 
drives it once round into 320 poles, or a mile. On the axis 
of this wheel is a pinion of twelve teeth, which, falling 
into the teeth of a fourth wheel having 72 teeth, drives 
it once round in twelve miles. This fourth wheel, carry¬ 
ing another index over the inner limb of the dial-plate, 
divided into 12 for miles, and each mile fubdivided into 
halves, quarters, and furlongs, ferves to regifter the re¬ 
volutions of the other hand, and to keep account of the 
half-miles and miles paifed over as far as twelve miles. 
The ufe of this inftrument is obvious from its conftruc- 
tion. Its proper office is in the furveying of roads and 
large diftances, where a great deal of expedition, and not 
much accuracy, is required. It is evident, that driving 
it along and obferving the hands, has the fame effeft a.s 
dragging the chain and taking account of the chains and 
links. 
Its advantages are its hardinefs and expedition; its 
contrivance is fuch, that it may be fitted to the wheel of 
a coach, in which ftate it performs its office, and mea- 
fures the road, without any trouble at all. 
The following is a defeription of an inftrument inven¬ 
ted by Mr. Edgeworth for the fame purpofe. “ This 
odometer ,” fays Mr. Edgeworth, “is more fimple than any 
which I have feen, is lefs liable to be out of order, and 
may be eafily attached to the axle-tree bed of a poft-chaife, 
gig, or any other carriage. One turn and a half of the 
ferew is formed round the nave of one of the hinder 
wheels by a flip of iron three quarters of an inch broad 
and one-eighth of an inch thick; this is wound round the 
nave, and fattened to it by (crews palling through five or 
fix cocks, which are turned up at right angles on the flit 
of iron. The helix fo formed on the nave of the carriage- 
wheel afts as a worm or ferew upon the teeth of the wheel 
A, fig. 6. upon the arbor of which another ferew of brafs 
B is formed, which afts upon the brafs wheel C. This 
wheel C ferves alfo as a dial-plate, and is divided into 
miles, halves, quarters, and furlongs; the figures indi¬ 
cating the miles are nearly three quarters of an inch long, 
fo as to be quite diftinft ; they are pointed out by the in¬ 
dex D, which is placed as reprefented in the plate, in 
fuch a manner as to be eafily feen from the carriage. 
Thefe two brafs wheels are mounted by the irons EE 
upon a block of wood F, eight inches long, two inches 
thick, and five inches broad. This block may be ferewed 
upon the axle-tree bed by two ftrong fquare-headed wood 
ferews. If the carriage permits, this block fliould be 
fixed obliquely on the axle-tree bed, fo that the dial- 
plate may be raifed up toward the eye of the perfon look¬ 
ing out from the carriage. H is a ratchet-wheel attached 
to the arbor of the wheel A, which, by means of the 
click I, allows the wheel to be fet with a key or handle 
1 fitted 
