DIO 
Drorrric Telefeoge, is a telefeope through which the 
hie't pailes dir ely from the objeé& to the eye of the ob- 
ferver. See 
Towards ie he of the 16th century, ‘the wonderful 
difcoverv of the telef{cope was accidentally made by. placing 
two glafs lenfes at the two extremities of a tube, and look- 
ing throu gh it. This difcovery was no fconer made, than 
= to im- 
aad which at ‘that time was looked as an oe 
able obftacle,. (fee Diopraics) fir Ifaac Newton con- 
ruéted a telefcope, which initead of an obj-@ gla als lens, 
a refleQtor; whence the rays of light, initcad . oe 
nefraced to a ee, were reflecded to a focus; and l 
ter cafe was not attended with a di one of the igh ia 
on’s c 
(iiuons exertions 
ontrivance int troduced 
telefcope, and of the refleding or catadiopiric tele{cope. ‘The 
former of thefe two kinds, which conttitutes the objet of 
the prefent article, confiits entircly of lenfes fixed in a tube 
er tubes; but the form, the number, and difpofition of thefe 
lenfes, has been mish: varied in order to a the aed 
And 2 
mpoun e objects 1 
is ce rincipally me for obferving ie ogee pide 
this fort of telefcope is very long, t ele are cone 
nected together not by a tube, but eg a rin or pole, and 
in that cafe it is called an aerial telefcope. 
By adding two or more convex fais to the eye tube of 
the attronomical telefcope, that inftrument is sone to re 
é hea telefcope, contrive 
onfilts of two lenfes ; but the eye le 
reprefents the object eredt, and peculy citing lea its field 
fv all, in comparifon € aflronomical te» 
ni ying ow 
common opera glafs 18, nothing more than a very fhort 
Galilean telcfcope. It magnifies little, but it fhews the ob- 
jeets ereGtand much illumined; hence it ismoftly ufed in places 
See the objects are rather 0 bfcure. 
The night telefcope is a fhort telefcope, of about two feet 
in length, and often fhorter. It reprefents the objecis in- 
verted, but much illumined $ though little magnified. Its 
field ot view is very extenfive ; hence it is ufzd moftly or en- 
and the 
latter for difcovering comets, or other not aie luminous ob- 
jeGs. 
Almof all thefe different telefcopes are often conftrufied 
6 
DIO 
with an achromatic obje& lens; in which = un epithet 
achromatic is state to their peculiar appeliati 
I, in Ancient Geography, a pevple placed by 
Picleimy ip the etea part of the ifland of T'aprobana. 
PHUS,a mountain of Afia, in eae near ‘the 
Araxet,y according to Plutarch: 
THOSIS, dower, in Surgery, an pa ies 
which crooked or dillorted members are made ven, and r 
ftored to their primitive and regular fhape. 
DIORYX, in ace Geography, a canton of Afia, in 
Affyria, near the Tig 
DIOSANTHUS, j in Botany, Aww; ades of Diofcorides, 
book vi. chap. 6, 1s merely enumerated by him among the 
coronary or ornamental plasts, without any siea aa eX- 
cept its being vk sae peas 
aah pau why fome conmentators have fuppofed this 
o be the Caraton, or Clove Pink, though others 
nee € mere correct who take it for the Sweet William, 
ser neus, however, has adopted the name, a little changéd, 
or his genus; to which er thefe plants belong. See 
Disxrets 
DIOSCOREA, (fo. a by Plumier ape the Greek 
io Pedacis Dioteo des.) ‘Phe Ya lum. Gen. gs 
Lin ae Schreb. 693. Mart. Mill, Di&. 
Ve De "Jeff, ee tay Cb . 
ae Ord. Sarimertacee, Linn, A, aragi 
Barren f. Cal. Perianth of one bell-fhaped 
leaf, in ‘fix deep, oblong fegments, fpreading 
mities ; the three innermott {maileft. Cor. none, except the 
calyx be taken for fuch. Stam. Filameuts fix, aw!-thaped, 
very fhort, oppofite to the fegments of the calyx ; anthers 
of two sae age Fert be ie ine as in the ba 
ones. Gor. n Pi 
rior; ftyles three, nee dels 
fule ‘large, three-lobed, wit 
haped, comprefled va'ves. a two ii eae cell, imbri« 
cated, el with a membranous bor 
Hexandria. 
Gen 
b arren fl. Calyx in fix sen fegments. Cos 
rolla none. Fertile fl. Cai deep fegments. Cor, 
none, Seis three. Capfule inferior, three-lobed, an 
ise ernest: comprefied, Seeds two in each cell, bors 
der 
Ob/ The capfule is juftly reprefented inferior in the 
Hortus jo though Linonzus, Juffieu, and Gartner 
thought it fu 
f this ae cook 20 fpecies are more or lefs aad 
nown, their fynonyms being reatly confufed. 
not at prefent furnifhed with materials to pina thea, for 
the plants being not very d:ffimular in appear 
markable for beauty, they have been but little prea ie 
y colle&tors, pai roots ere generally tuberous, ae 
e ie when Stems annual, twining, wea 
Leaves moftly sles talked, heart-fhaped, entire, with 
numerous fimple ribs. Flowers in fimple or branche 
yah ers, {mail, greenifh-white. Tuberous buds, which be- 
roots, are frequently a on the fiem above the 
taltalks. ativa, Linn. Sp. Pl. 1463. 
nferton of the ae 
HR ot 
say sui ded as {uch in the 
But Forfter, in his Plante Piulove 5s we ays alata, 
Linn. Sp. Pl. 1462, is the moft rata cultivated in 
both Eaft and Weft Indies, the equinoétial part of Africa, 
and in the iflands of the South Sea, its sar rare no lefs 
grateful than wholefome, when either boiled or — and 
ioape . - ad. This is the Katsjtl Kelengt of Hor a 
8; and, according to Fortter, the di dee fpecies 
of ‘Cine in- Rumph. Herb. Amboin. v. 6. book 9. 
