DEC

228

DEC

When the leaves are thinner than half an inch, the deal willdivide into five or more parts, and is therefore termed five-cutstuff, and thus the qualifying word is applied according tothe number of pieces. Whole deal is one inch and a quarterthick, and slit deal the half of that.

Deals are formed by sawing the trunk of a tree intolongitudinal pieces, of more or less thickness, according tothe purpose they are intended to serve. They are renderedmuch harder by throwing them into salt-water as soon asthey are sawn, keeping them in three or four days, and after-wards drying them by exposing them to the air: but neitherthis nor any other method will preserve them fromshrinking.

The quality and well-seasoning of deals are very essentialto the construction of buildings. They are employed innaked flooring, partitions, the hoarding of floors, doors,windows, architraves, cornices, mouldings, dados, plinths,bases, surbases, wainscoting, linings, columns, pilasters,chimney-pieces, &c.

White deal should only he used for inside work, as in bed-chambers ; it is less liable to shrink than yellow, and beinga cheaper article, is to be preferred in panelling. Yellowdeal, on account of its hardness, from being saturated withturpentine, is more fit to endure violence and exposure to theweather.

DEBASED, a term applied to that style of English archi-tecture, so to speak, which succeeded the Late or PerpendicularGothic , and in which some peculiarities of the Italian stylebegan to be introduced. For more detailed information. SeeGothic Architecture.

DECAGON (from coca, ten, and ywvla, an elbow orcorner) a plane figure, with ten sides and angles. If all thesides and angles be equal, it is called a regular decagon, andmay be inscribed in a circle : the method is thus : first de-scribe a pentagon, as is shown under that article; bisect eachof the arcs, of which the sides of the pentagon are chords ;join every point of bisection to the extremity of eachadjacent chord, and the decagon will be completed.

If the side of a regular decagon be 1, its area will5/ \2

be 5 + 2 (5) J =7.6942088.

To find the area of a regular decagon : multiply thesquare of the side by 7.6942088, and the product will givethe area : or, for practical use, multiply the square of theside by 7.6942.

Example. What is the area of a decagon, the side ofwhich is 25 feet ?

25

25

125

50

DECAHEDRON (Greek, Lra, ten, and eSpa, aA solid figure contained by ten sides.

DECAMETRE (Greek, Seva, ten, and gerpor, to

a French linear measure containing ten metres, and H393.71 English inches. fft.nde 1 ’ 3

DECANICUM, a prison in which ecclesiastical °were confined. . fctciu

DECASTYLE, or Decastylos (from theten, and vvXoe, a column) a colonnade, or front ol a 1consisting of ten columns. tb e

DECEMPEDA (from the Greek, cmavrovc ; ° r ^ usedLatin , decern, ten, and pes, pedis, foot) a ten-foot i .’ )C |,eS>by the ancients : the foot was subdivided into tw ®J v , gr<dd'and each inch into ten digits. This rod was used >tects to give the proper dimensions and proportionsbuildings. e id 1 ®

Horace (lib. ii. od. 15) blaming the magnified” . £

delicacy of the buildings of his time, observes,

that ] ], e

- ■ hi

otherwise in the times of Romulus and Cato;

tb8t wn o'#

houses of private persons, there were not then ' turn ed i0porticos measured out with the decempeda, »° rthe north to take the cool air. :« tb 6

The decempeda was also used in land-measurmn’

in

bet

ins

nuim

denon» ni ( f0 „ r

same manner as our chain.

DECIMAL (from the Latin , decimus) anycreasing by the order of tens. f f act>^

Decimal Arithmetic, the art of computing flS diwhose denominator is 10, 100, &c. Decimal fra° =from vulgar fractions in this ; that thewritten ; instead, of writing r 4 ff , __ JUO ,be written decimally, .4 or .15. The decimal p°it is used to distinguish it from whole numbers.

To reduce any vulgar fraction to a decimal, sa /’

As the denominator of the vulgar fractmis to the denominator of the decimal,so is the numerator of the vulgar fractmto the numerator of the decimal. . n

Example. To reduce | to a decimal frac i ’denominator is 10.

It will then be as 3 : 10 : : 2

10

i»'

81 20

but then <l ,e Jo 6,

so that 6 is the numerator required : »“■ ^ oT eremainder of 2, consequently the numerator is ■■but less than 7 ; thereforewhose numerator consists of a single unit,nearer to the truth, we must then suppose ^qqof the decimal to be divided into more parts, sayThen again 3 : 100 : : 2

2

it is the nearest j n e oS-the

fr#® .tn 1

den> 1 ‘

i

i

625

7.6942

1250

2500

5625

3750

4375

4808.8750 equal the area required.

This figure may also be measured by the general rule offinding the superficial content of any polygon whatever.See Polygon. 1

3) 20066

.11 ^

. «« is too snwji toobut here is still a remainder of 2, that is, o 6 e is s g67 too great, therefore the decimal fraction i a ^ t ]i esmall ; 66 is, however, a greater portion 0 tru^ 1 , th®*of 10 : we have therefore come nearer to ^ tlS fi" 1 V tl* elatter operation than in the first. We sha ^juat 01 b eif the number arising by multiplying the deI , ar fr»® ! „, f* 1decimal fraction by the numerator of the v ^ (rar fra® ^ po* enot divisible by the denominator of the v givincrease of the denominator of the decima