DIA 
to the fine of the ftyle’s height for by ye ae sabia 
triangles, ra rad.:S.PZ:: S.PZov : 
latitude is to radius as the tangen ee is to 1. — 
eo of the ue $ ee ernceaee for, rad. : cof. PZ 
: ta : ta v.cotang. PZ v. 
ee ‘the houe angles it w be, as radius is to the fine of 
the pole’s height, fo is the nee of the hour-arc from the 
meridian of the plane to the tangent of the hour angle from 
e VU, 
; and therefore bs find i iV, 
faye rad. S. Pus: tang. ¢P v : tang. fv = 
the centre, or hour-angle. That thefe feveral conclufions 
nan sek equal to Z V, asit a be. For they 
i of the {phere, which 
And ii mete the dial- plane 
HA inZ and v, and Z v meafures that a at the centre. 
For the fame reafon, ¢v meafures the here angle from the 
fubflyle. Again, Pw meafures the angle of the ftyle above 
oe fubftyle. For Pw is perpendicular to HA, and the 
cP v ee angle formed at the centre of the {phere, 
of the dial ; one fide being the axis drawn 
he other ie fubftyle rawn from orcover, 
Z Pw has been fhewn to be the plane’s difference S longi- 
tude. It appears bene that the piane’s differencce of lon 
For the 
: ie tke one, and the arc Z Vv the other. Agan, every 
te on the {phere is converted into the hour- angle in 
ial, by =~ So the fame two hour-circles, 
y differe 
Thus, 1. For ead the fab ftyle? 8 diftance 
la 
» of pole’s height wi the ne : 
: ion : Cah the di nenee a the fubityle pen 
lus: S. Aeon or co 2: tang. 
of the po ie heishe above the plane Py S. of the 
fobityle s diftance 2. For finding the yea 8 pg 
cot. of fubftyle’s Glens Zu: &. lat. Z 
3 _ : cof, ftyle’s height Pv rad. :S. fobyte 8 
diftance, Zv i: cotang. eect oh 6 or eae. PZo ang. 
of thyle? 8 en Pu. 3. For the plane’s differen of : ongi- 
tude; os lat. or S a i rad. < ¢ Bz ae 8 alse Zv 
: S. plane’s difference of long de, Z Or, rad. 
tang. sae or cotang. : tang. fyle’s height Po: cof, 
e’s di aa of longitude, Pie rad. : cof, 
n,o.P : : 
s pie of eet de, v, Mrs ey “fyle’s 
of, 7 : S.0 
‘<% a ‘fyle’ s haan 
pa : ere tr tang. of fubltyle’s dilkance, Zv : tang. of 
plane’ s diff, of longitude, ZP On a feale the feveral re. 
ufing it. connt the plane ¢ line of chords, 
aud a line drawn Reseed acrofs, will irterfe€t all the other 
lines in their proper points ; he numbers of pradua- 
tion will indicate, and thefe give all the requifites ou 
calcula 
Wher : a ‘ee of this fort is not to be had, the requifites 
may b. found by Gunter’s feale, e xtending upon the levera 
lines, Ss to the rules and proportions laid down for 
pofe. 
that pur 
8 
} 
enthufiafm, and the 
DIA 
Drarting Sphere, is an inftrument made of brafs, with 
fe aes femieciretes fliding ov 
zon, to demonftrate the nature of the do@rine of {pherical 
ee ad to givea true idea of the drawing of dials on 
all manner of pianes 
Diartuinc, ina Mine, called alfo shai : us ufing of 
a compafs (which they call dial), andalon » to know 
which way the load, or vein of ore rere or ia to fhift 
an air-fhaft, or bring anadit toa defired place. See Mininc, 
art Ry and Piu 
In ses ween one of the Derbythire mining laws, di- 
ns are given for the practice of dialling, wherein a ‘dial. 
is : defer bed; whofe circle is divided into 32 points each 
— 
rr —, and each of thefe into 4 pricks, each = 2. 
Cary, in the Strand, manufa€tures — or ate compafa 
boxes, ni a fmall refletor in t id that turns on an 
by means of whi ot ftanding up on the 
oppofite fide of the nah obferations can be made either ta 
a candle under-ground, or to an object above-; round, and 
its azimuth conveniently and accurately afcertained, 
DIALOGISM, Ararcyiryos, in Rhetoric, is aa for the 
foliloguy of perfons deliberating with ii We have 
an initance of it in Virgil, where Dido fay 
sal 
in e5 
“En quid : Susp ? rurfufne procos ae priores 
Experiar ? &c,”’ 
7 aie fenfe, it is diftinguifhed from dialogue. Voff. Rhet. 
p- 355. See Diarocue. 
ee cis is alfo taken in a more extenfive fenfe for difa 
courfein general, whether held by a perfon alone or in coms 
n 
DIALOGUE, a arene * a . more perfons, 
real or feigned, either by word o » or in writing. 
The word 1s formed from ae Latin dialogs of the Greek 
diroy@-, which fignifies the fam 
al inftru@tion. 
Ener, Feces Bafil, Choon. Ke. hae ufed this 
mode of infiru€tion. 
Antiquity made ufe of dialogue, not only on pr eeicur 
and comical fubjeéts, as Lucian did, but ae on the 
ferious and ablira&t: fuch are the dialogues of Plato, and 
thofe of ne which turn altogether on “fabjetts of eiee 
fophy or p 
lato is ervey Se for the beauty of his dia. 
logucs. The fce 
parable to Plato; the only fault of his imagination is fuch 
an excefs of fertility as allows it fometimes to obfeure his 
udyment. It frequently carries him into allegory, fiction, 
airy regions of myftical theology. The 
philofopher is, occafionally, loft in the He affords, 
however, much edification ; ; but whether we be edified bills 
the matter or not, we are always entertained with the 
ner, and left ee a ftrong impreffion of the tes of 
the a 8 geniu 
ero’s di Sirus s, or thofe recitals of converfation which 
he ee introduced into feveral of his philofophical and critical 
works, are not fo {pirited, nor fo charaGteriftical as thofe of 
Plato, 
