P L A 
600 
ferring with him on the fubjeft. The refult of this con¬ 
ference was, that, being a fubfcriber to the Royal Infti- 
tution from its firll eftablifhment, and havingconfequently 
an interefl in promoting its fuccefs, Dr. Pearfon agreed 
to calculate, contrive, and draw a plan for, a new inftru- 
ment, which was accordingly done, and put into the 
hands of Kenneth lVPCulloch, an old but ingenious 
workman, employed at tbac time in the w'orkftiops of the 
inftitution. The materials being prepared, the machine 
was begun in the fummer of 1802, and finifhed in that of 
1803, after having been ufed in an unfinilhed Hate in the 
fpring courfe of lectures of the latter year. The arrange¬ 
ment and dimenfions of the various parts of the machine 
are fully defcribed, with two beautiful engravings, in 
Rees’s Cyclopaedia, by the Rev. Dr. Pearfon himfelf. Itis, 
indeed, the moll complete inftrument of the kind that can 
be imagined. 
PLAN'ETARY, adj. Pertaining to the planets.— 
Their planetary motions and afpefls. Milton's P. L. 
Defcribe the liars and planetary way, 
And trace the footlteps of eternal day. Granville. 
Under the denomination of any particular planet.—I 
was born in the planetary hour of Saturn, and, I think, 
I have a piece of that leaden planet in me ; I am no way 
facetious. Addifon's Spccl. 
Darkling they mourn’d their fate, whom Circe’s power, 
That watch’d the moon and planetary hour, 
With words and wicked herbs, from human kind 
Had alter’d. Dryden. 
Produced by the planets.—We make guilty of our dif- 
allers the fun, the moon, and liars, as if we were villains 
by an enforced obedience of planetary influence. Shake - 
Jpcare’s K. Lear. 
Be as a planetary plague, when Jove 
Will o’er fome high-vic’d city hang his poifon, Shakefp. 
Having the nature of a planet; erratic: 
We behold bright planetary Jove 
Sublime in air through his wide province move; 
Four fecond planets his dominion own, 
And round him turn, as round the earth the moon. 
Blachmore. 
PLAN'ETED, adj. Belonging to planets : 
Tell me, ye liars, ye planets ; tell me, all 
Ye ftarr’d and planeted inhabitants, what is it, 
What are thefe fons of wonder ! Young's Night Th. 
PLANET'ICAL, adj. Pertaining to planets.—Add 
the two Egyptian days in every month, the interlunary 
and plenilunary exemptions, the eclipfes of fun and 
moon, conjundlions and oppofitions planetieal. Proton .— 
Some planetical exhalation, or a defcending liar. Spenfer 
on Prod. 
PLANGOT'TA, a town of Bengal: twenty-one miles 
north-north-well of Kilhenagur. 
PLA'NIARY, a town of Bohemia in the circle of 
Kaurzim : three miles north-north-eaft of Kaurzim. 
PLANIE'R, a fmall illand in the Mediterranean, near 
the coafl of France. Lat. 43.12. N. Ion. 6.19. E. 
PL ANIFO'LIOUS, adj. [planus and folium, Lat.] 
Flowers are fo called, when made up of plain leaves, fet 
together in circular rows round the centre, whofe face 
is ufually uneven, rough and jagged. 
PLANIL'OQUY, f. [from the Lat. planus, plain, and 
loquor, to fpeak.] The a£t of fpeaking plainly. Scott. 
PLANIMET'RICAL, adj. Pertaining to the men- 
furation of plane furfaces. 
PLANIM'ETRY, f. [planus, Lat. and Gr. 
I meafure.] That part of geometry which confiders lines 
and plane figures, without any confideration of heights 
or depths.— Planimetry is particularly reltrained to the 
men(uration of planes or furfaces ; in oppofition to 
Jlereomctry, or the menfuration of folids. Chambers. 
PLA'NING, /. The acl of fmoothing a board, manu¬ 
ally, with a plane. See Plane, p. 592. But machines 
are now ufed to fuperfede this great manual labour. 
Planing Machines are of modern invention ; the 
firlt, we believe, was projedled by general Bentham, who 
obtained a patent for it in 1791. It confifted of a plane 
to be put in motion by means of a crank turned by a 
mill, to give it a reciprocating motion ; or on a fmaller 
fcale it might be worked by hand in the ufual manner, 
but the plane was fo formed as to require none of the 
fkill and attention neceflary in the ordinary method of 
operating. It is well known that, in planing a board, the 
workman, befides exerting the force neceflary to force 
the inftrument along, has feveral points to attend to; 
even in the Ample cafe of planing a ftraight board, he 
muft adjuft his tool to the board in a proper manner for 
beginning the ftroke, and employ fufficient force to keep 
it down to the board; and, in returning, he muft raife it 
up off the board fufiiciently to fave the cutting edge from 
injury; he muft alfo guide it fideways to prevent its 
flipping off the board ; and, if this be wider than the 
plane, he muft conftantly examine if he reduces the 
middle and the fides in the proper manner to make a 
plane furface ; and, laftly, he mull obferve the marks he 
previoufly makes for the thicknefs of the board, that he 
may keep it parallel, and not reduce it too thin. By 
the general’s invention, all thefecircumftances are gained 
at once; the plane is made the full width of the boards 
intended to be planed, and on each fide of it fillets or 
cheeks are fixed, which projedl beneath the face of the 
plane juft as much as the thicknefs the board is to be re¬ 
duced to : thefe cheeks, therefore, guide the plane fide¬ 
ways in pafling along the board, and gauge it in thick¬ 
nefs; becaufe, when the board is reduced to the quantity 
which the cheeks are beneath the furface of the plane, 
the cheeks reft upon the bench or furface on which the 
board lies, and bear off the plane, fo that it can cut no 
longer. The plane is kept down by its own weight, 
which is increafed, when neceflary, by loading it with 
weights ; and thefe are contrived to be capable of fhifting 
their pofition from one end of the plane to the other 
during the time it is making the ftroke; becaufe at firffc 
the preflure is required at the fore end to enter the cut, 
but at the conclufion it muft be greateft at the hinder 
end, to prevent the fore end tripping down the inftant it 
leaves the board. By another contrivance the plane is 
caufed to rife up fufficiently to clear the cutting edge 
from the wood when the plane is on its return. It is by 
a piece which a£ls as a handle to the plane, and to which 
the power is applied, that it is fixed in the manner of a 
lever upon an axis extending acrofs the width of the 
plane, and carrying at each fide thereof a fhort lever, pro¬ 
vided with rollers in their extremities; the handle projedls 
upwards from the plane, which, being forced forwards by 
it, affumes an inclined pofition, as do alfo the fhort levers, 
and their rollers then rife above the cheeks of the plane; 
but, when the plane is drawn back, its handle is firlt drawn 
back into an erefl pofition, and the levers moving with 
it, their rollers projedl beneath the cheeks of the plane, 
and raife it off the'bench, the plane being in its return 
borne by them. 
The bench for fupporting the board during the 
operation is alfo of a peculiar confirmation, in order to 
confine the work fteady upon it. In cafes when the 
boards to be planed are winding or irregular on the.lower 
fide, fo that they cannot lie flat upon the bench, it is pro¬ 
vided with two fides, which can be brought toclofe upon 
the edges of the board, and hold it fteady between them, 
being furnifhed with one or more rows of flat teeth to 
penetrate the wood and retain it; thefe fides are con¬ 
trived to rife or fall upon the bench, to accommodate 
the different thicknefies of the boards. When a very 
thin board is to be planed, it might be liable to fpring 
up to the iron, fo as to be reduced even after the plane 
came to reft with its cheeks upon the bench; to avoid 
